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BAROMETRIC PRESSURE

PAUL BERT Born October 17, 1833. Died November 11. 1886.

BAROMETRIC PRESSURE

Researches In Experimental Physiology

PAUL BERT

Translated from the French by

MARY ALICE HITCHCOCK, M.A.

Formerly Professor of Romance Languages at the University of Akron

and

FRED A. HITCHCOCK, Ph.D.

Associate Professor of Physiology at The Ohio State University

0 I.

COLLEGE BOOK COMPANY

COLUMBUS, OHIO

1943

Copyright 1943

By

COLLEGE BOOK COMPANY

F. C. Long, Proprietor

THE F. J. HEER PRINTING COMPANY

Columbus, Ohio

1943

FOREWORD

It can be said of Paul Bert as it has been of Vesalius, Harvey and Boyle, that the full significance of his work could not be fully appreciated until long after his death; but it is tragic that the chaos of a far-flung war was required to bring Bert's work into its full meaning and perspective. At a time when altitude physiologists and flight surgeons are being feverishly trained by all countries at war, it becomes of first importance to English-speaking peoples that the great classic of altitude physiology should be made available in the English language. Copies of the original French edition are exceedingly rare, and one therefore cannot praise too warmly the industry of Professor and Mrs. Hitchcock in preparing the English rendering, and the patriotic foresight of the publishers in thus mak- ing the text available to the flying personnel of our Armed Forces. That such a task could be accomplished in the midst of war is of itself gratifying, for it bears evidence that our perspectives and our scholarly traditions are being maintained and will survive during these years of stress and fury. As Professor Sigerist recently re- marked in reviewing Howard Adelmann's translation of Fabricius, "Today when everyone thinks in military terms I would like to stress that the publication of such a book at such a time also repre- sents a victory equally important to the capture of a strategic hill and more endurable. One can have full confidence in the fu- ture of a nation which in the midst of a bloody war possesses the intellectual and technical resources to produce such a document of scholarship."

The details of Bert's life are not widely known and it seems ap- propriate here to give a brief sketch of his meteoric career. Among his contemporaries Bert was probably better known for his pioneer studies on skin grafting — work that did much toward fostering the specialty of plastic surgery during the war of 1870 — than he was for his studies in altitude physiology. Indeed in a notice published

in the Lancet on November 20, 1886, shortly after his death, there is no mention of La pression barometrique and little to suggest that Bert was a great physiologist.

Born at Auxerre on October 17, 1833, Paul Bert received his early education in the Department of Yonne. He had chosen en- gineering for his profession and had entered the College de St. Barbe with a view to preparing for the polytechnic school. He was dissuaded from this in favor of the law and passed his bar exam- inations successfully. But he soon found the law boring to his inquisitive mind and, for the third time, modified his course of study on becoming acquainted with Gratiolet, the Director of the Anatomical Museum in Paris. He eventually obtained his M.D. degree in 1863 at the age of thirty. During his years at Paris he had come under the influence of Claude Bernard in whose labora- tory he served as an assistant. Bernard recognized his ingenious mind and predicted a brilliant future. His thesis, published in 1866, on the grafting of animal tissues, attracted wide notice, and it won for Bert in 1865 the prize in experimental physiology offered by the Academie des Sciences. After teaching zoology for several years at the Faculte des Sciences at Bordeaux, he was appointed in December 1869 as Bernard's successor to the Chair of Physiology at the Faculte des Sciences at Paris. Bernard at the time occupied two chairs, one at the Sorbonne, the other at the Faculte, and he resigned the latter to make place for his brilliant pupil.

During the last two years of the Second Empire, Paul Bert made himself conspicuous in the political world by his uncompromising republicanism and at the fall of the Napoleonic dynasty in 1870, he was rewarded by Gambetta with the Prefecture du Nord. Elected Deputy in 1871, he became noted for his constant opposition to re- ligious congregation, which led eventually to the decrees of expul- sion against the Jesuits, Dominicans and other orders. He was in- sistent that the state schools should be taught not by nuns and friars, but by non-sectarian personnel. In 1881 he was made Min- ister of Public Instruction in Gambetta's famous Grand Ministere, but he fell with his chief after an ephemeral exercise of power.

Following the death of Gambetta, Bert's political influence was on the wane and he returned to his scientific pursuits, obtaining a vacant chair in the Academie des Sciences. At the beginning of the year, the attention of the French Government was forcibly drawn to the highly unsatisfactory state of affairs in French Indo-China's Province of Tongking, and it decided to send out a Resident Gen- eral vested with special powers to effect a thorough reorganization.

VI

Paul Bert was chosen for the post since he had always supported the French colonial policy, and he departed for the East in Febru- ary, 1886. He was enormously active during his first five months at Hanoi and did much to effect a complete reorganization of the Tong- king government; but in November he became suddenly ill and died of dysentery on November 11th, at the early age of fifty-three.

Paul Bert's activities had turned to altitude physiology about 1869 as a result of his friendship with a Dr. Jourdanet who had be- come interested in mountain sickness through personal experience while travelling in Mexico. Jourdanet was a wealthy patron of the arts and sciences, and he gave Bert the essential financial support for altitude studies, making it possible for him to develop several low-pressure chambers for man and animal. In the course of his investigations, Bert had sponsored an ascent in a balloon, Zenith, in which various determinations were to be made of the constitu- tion of the upper air (April 15, 1875) . This ill-fated expedition was undertaken by three balloon enthusiasts, MM. Sivel, Croce-Spinelli, and the only survivor of the expedition, Gaston Tissandier. The ac- count of the trip may be given in Tissandier 's words:

"I now come to the fateful moments when we were overcome by the terrible action of reduced pressure. At 22,900 feet . . . torpor had seized me. I wrote nevertheless . . . though I have no clear recollection of writ- ing. We are rising. Croce is panting. Sivel shuts his eyes. Croce also shuts his eyes. ... At 24,600 feet the condition of torpor that overcomes one is extraordinary. Body and mind become feebler. . . . There is no suffering. On the contrary, one feels an inward joy. There is no thought of the dangerous position; one rises and is glad to be rising. I soon felt myself so weak that I could not even turn my head to look at my com- panions. ... I wished to call out that we were now at 26,000 feet, but my tongue was paralyzed. All at once I shut my eyes and fell down powerless and lost all further memory."

The fatalities on the Zenith were due, in some measure, to com- petitive braggadocio, for the English balloonist, Glaisher, in 1862 had ascended to 24,000 feet and the Tissandier expedition wished to outdo him. They had little notion of the dangers, nor were they aware of the peril of the fixation of ideas that develops under low oxygen tension.

Paul Bert began to work actively on respiratory problems early in the seventies, and in 1874 published a preliminary monograph of 167 pages entitled: Recherches expcrimentales sur Vinfluence que les modifications dans la pression barometrique exercent sur les phcno- mcnes de la vie. This is taken up in part with a description of his admirably constructed low-pressure chamber. In 1878 he published

VII

the book here translated which has become one of the great land- marks of physiology — a book which stands as the very cornerstone of modern altitude physiology, La pression baromctrique. Re- cherches de physiologie expcrimentale , containing 1178 pages and 89 text figures. The first 522 pages deal with the history of altitude physiology up to that date; and if Paul Bert did nothing else, we should be lastingly in his debt for this masterly historical presenta- tion— a model, be it said, for any student wishing to write in the field of medical history. The second part, occupying 518 pages, con- tains experimental protocols; the third and final part, which runs to 118 pages, contains his resume and conclusions, and is again a model of concise, orderly and logical scientific presentation.

What precisely did Bert prove? There had been sharp diver- gence of opinion whether mountain sickness was due to diminution of barometric pressure per se, or to diminution of oxygen pressure. Bert performed critical experiments, keeping the absolute pressure of oxygen constant while lowering the total atmospheric pressure, repeating them time and again both in animals and man. By so doing he proved beyond all doubt that the principal symptoms of altitude sickness arise from reduced partial pressure of oxygen and not from diminution of total pressure. He thus applied for the first time to human respiration Dalton's concept of partial pressure which has become the basis of all subsequent work in the field of altitude physiology.

In one of his vivid lectures on the history of physiology, Sir Michael Foster said that science travels in circles: the concept fol- lowed yesterday may be dropped today and rediscovered tomor- row. One of those who did not accept Paul Bert's conclusions was that picturesque physiologist of Italy, Angelo Mosso, who main- tained that at altitude one breathed so deeply that carbonic acid was lost with resulting alkalosis, and that oxygen-want played only a small part in mountain sickness, the major symptoms be- ing due to "acapnia"— loss of carbon dioxide. Few in this century, save Yandell Henderson, have paid due attention to Mosso and acapnia, but we are coming once again to heed what he said. More is known now about acid-base relationships in blood and tissues. The carotid sinus reflexes have also been discovered. When blood of low oxygen saturation reaches the carotid sinus, a reflex in- crease in depth and frequency of respiration occurs. The partial pressure of oxygen is a primary and determining stimulus as Bert maintained; but under conditions of low oxygen tension, hyper- ventilation of serious proportions may occur, and we have reason

VIII

to believe that pilots in the higher altitude ranges may in some circumstances hyperventilate to such an extent as to bring on tetany and even loss of consciousness.

Thus the pendulum swings; and if we wish to gain perspective for tomorrow, we look to the past and to the work of men like Robert Boyle, Paul Bert and Angelo Mosso who give us courage and inspiration to face the future.

John F. Fulton. Yale University, August 15, 1943.

IX

TRANSLATORS' NOTE

In his preface Paul Bert comments on his use of direct quota- tions in the historical part of this book in the following words, "In my bibliographic research I have repeatedly seen the affirmations of an author changed to negations by a series of translations and analyses." Again in a footnote on Chapter II he calls attention to the fact that a passage which he quotes from the French translation of the account of the balloon flights of Glaisher and Coxwell did not occur in the English text and adds, "Can it have been added by a fanciful translator? Traduttore, traditore" (translator, traitor). This evident distrust of our author for translators has been con- stantly in our minds and our translation is, therefore, somewhat more literal than it might otherwise have been. This policy has resulted in the use of certain words and expressions that are old fashioned; for example, we have used the word hematosis to mean arterialization of blood and we have retained the expression car- bonic acid, even where our author is obviously referring to carbon dioxide.

In only two respects have we departed from the plan followed in the French edition. First, the footnotes, instead of being placed at the bottom of the page on which the reference occurs, have been grouped together and put at the end of the several chapters. This method is made mandatory by the mechanics of modern type set- ting, and also greatly improves the appearance of the page. Second, we have added an index. In the French edition there was no index and the detailed table of contents together with the list of illustra- tions was placed at the end of the book. In the English edition these have been moved to the front of the book and the index put at the end.

We wish to acknowledge our indebtedness and express our grati- tude to the John Crerar Library of Chicago for the uninterrupted use of a copy of the original French edition of La Pression Baro- metrique over a period of more than two years. Copies of the book

XI

were also loaned us for shorter periods by the Library of Congress and by the Aero-Medical Laboratory at Wright Field. Photographic copies of the illustrations in the original edition from which the plates for the present volume were prepared were furnished us by the staff of the Wright Field Aero-Medical Laboratory. We are grateful to Colonel Otis O. Benson, Jr., who arranged to have this done.

Various agencies of the Ohio State University were of consider- able assistance in a number of ways. Funds to help defray the cost of clerical assistance were furnished by President Bevis, and by the Graduate School upon the recommendation of Dean Alpheus Smith. The staff of the library furnished assistance whenever called upon, and Mr. Oscar Thomas and Mr. John B. Fullen of the Alumni Office were of great assistance in a variety of ways; we are especially grateful to them both.

Finally, we want to thank Professor John F. Fulton of Yale University not only for the preparation of the foreword, but also for his enthusiastic support and valuable advice throughout the entire project, and Mr. F. C. Long of the College Book Company, without whose vision and faith in Paul Bert the publication of the complete translation would have been impossible.

It is with some hesitation that we turn the manuscript over to the printer. It contains errors and imperfections. Many of these could be corrected by further revision, but such revision takes time and in the present state of the world it seems desirable to make Paul Bert's classic work available to the many English speaking investigators in the field of aviation medicine with as little delay as possible. We have therefore foregone further revision and polish- ing. We know nothing would please Paul Bert more than the knowledge that his work had been of use to the Allied Nations in their struggle to free his beloved country from the shackles of its traditional enemy. Paul Bert was a liberal, a humanitarian, and a loyal patriot, as well as an outstanding scientist. During the months that we have worked on the translation of his great book our admiration and respect for him have grown. It is our sincere hope that we have made none of his affirmations negations and that we have been translators without being traitors.

M. A. H. F. A. H.

XII

TO DOCTOR JOURDANET

My dear Colleague:

It is to you that I owe, not only the first idea of this work, but also the material means to execute it, which are so difficult to collect. I have been very happy to see physiological experimentation on one of the most important points of my study confirm entirely the theory which your intelligence had deduced from nu- merous pathological observations collected on the high Mexican plateaux. For all these reasons I should dedi- cate this book to you, and I do so with the greater pleasure because you are one of those persons who would make gratitude easy to even the most thankless natures.

Paul Bert.

XIII

PREFACE

No one doubts the considerable influence which changes in baro- metric pressure can exercise on living beings; we are even inclined to exaggerate its importance. If the barometric column rises or falls some millimeters, nervous or asthmatic people experience favorable or painful symptoms which they attribute to the heavi- ness or the lightness of the air. If this were really the cause, a walk from the banks of the Seine to the top of the Butte Mont- martre or the converse should produce similar results in the same people.

But outside this group of data, to which I shall return in a mo- ment, many remain which present a much greater interest, and which deserve to be studied with perseverance.

Are we dealing with increase in pressure? When, in the shafts of a mine or in the caissons intended to become the piers of a bridge, workmen are protected against the invasion of the water by air compressed by powerful machines to several atmospheres, they experience strange and sometimes dangerous symptoms dur- ing or after their stay in compressed air. Likewise divers who gather pearls, sponges, or coral, or attempt the salvage of sunken ships, furnished with diving apparatus and breathing an air whose pressure is proportional to the depth they reach, are frequently stricken by paralysis or death. On the other hand, medicine, mak- ing use of observations that are already old, has attempted with considerable success to make use of the influence of air at suitably low pressures, since the time of Junod, Pravaz, and Tabarie.

Are we dealing with decrease in pressure? We can mention first the symptoms which threaten aeronauts when their ascent brings them to heights above 4000 meters: nausea, vertigo, hemor- rhage, syncope; then the phenomena which have been known much longer by all those who have attempted the ascent of mountains of over 3000 to 4000 meters, mountain sickness, about whose cause

XV

so many strange hypotheses have been suggested. Finally we find here data of a much greater importance. It is no longer a matter of a few workmen, a few invalids, or a few tourists, but of whole populations which normally and regularly live, construct cities, group themselves as peoples, in these lofty places where painful and sometimes unendurable sensations await the traveler.

We feel that here our problem affects not only the hygiene of peoples, but also to a certain point, their history and politics. In the Himalayas, in the Cordillera of the Andes, populous cities are built at heights greater than that of our Mont-Blanc, where no one completely escapes mountain sickness; in Mexico, thousands of men live on the plateaux of Anahuac, at an average height of 2000 meters; the great civilizations of the Mayas and the Nahuas had their maximum of development between 2000 and 4000 meters above sea level.

The reader can see by this brief survey in what important points the question affects the experimentation to which I have conscientiously devoted myself. It will consequently seem natural that such phenomena have given rise to numerous publications by doctors or travelers; but he will no doubt be surprised that so little has been attempted in laboratory experimentation to explain their cause. The simplest idea apparently would have been to construct apparatuses permitting one to reproduce changes in barometric pressure, isolating them from secondary conditions, uncontrolled variables, which inevitably accompany them in the state of nature, and to examine the immediate results of these changes on man and on animals. Now very little has been done in this direction. On the other hand, we shall find incomplete observations, pretentious dissertations, and probable or absurd explanations in great number.

My purpose has been to fill this considerable gap, and to solve these important problems by a purely experimental method.

In taking my position thus on solid ground, I had to set aside systematically three kinds of questions which could not be attacked in the laboratory, and for which consequently absolute conditions of proof could not be collected; that is: daily variations of the barometer, therapeutic applications and acclimatization in lofty places.

I do not regret the first question, which does not seem to me even to belong to our subject of study. Slight modifications in air pressure revealed by the barometric column in a given place are accompanied by too many other meteorological phenomena (hygro- metric, electric, etc.) for anyone to determine the part, certainly very small, which they play in the condition of certain invalids.

XVI

\ ■

As to the other two questions, I have made great use of data given by authors who have discussed these topics, and I think that my own studies will not be without value in guiding physicians and hygienists in the midst of the innumerable difficulties which these questions involve. But I have not handled them directly, not only because of my medical incompetence, not only because labora- tory experiments on birds, dogs, or even men could hardly settle them, but also for a special and rather personal reason.

Eight years ago, when Dr. Jourdanet, well known for his re- markable studies on the climatology of Mexico and for his theory of the anoxemia of altitudes, offered— with a generosity for which I hope the results of my work might be worthy recompense— to put at my disposal all the material means required by the re- searches whose importance and difficulty I had publicly indicated x in 1868, a sort of tacit agreement was established between us. I was to limit myself to studying experimentally in the laboratory by means of my instruments the modifications which changes in baro- metric pressure would produce in the vital manifestations of ani- mals or plants. Whatever the extent of my experimental equip- ment, these changes evidently could not be of long duration, so that if they were to produce convincing results, it was absolutely necessary that they should be extensive. Besides, this is the pe- culiar characteristic of laboratory experiments.

M. Jourdanet properly reserved for himself the study of the effects produced by slight variations in barometric pressure, acting either for a rather brief time upon invalids — a test the exquisite delicacy of which will always terrify experimenters a little— or for years upon the same individuals, or for centuries upon successive generations, joining their effect to those of so many causes known or unknown; dangerous problems, but very likely to fascinate a wise and eager spirit, aided by an eloquent pen.

We both accomplished our tasks; two years ago, M. Jourdanet published his fine book, Influence of Air Pressure on the Life of Man: Altitude Climates and Mountain Climates.2

As for me, delayed by efforts outside the field of science, too often called from my laboratory by important civic duties, it is not until today that I present the properly arranged results of my long researches.

The present book which, if I am not mistaken, holds interest not only for physiologists, but also for physicians, engineers, and even travelers, is divided into three parts: history, experiments, con- clusions.

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I have given the greatest pains to editing the history. I have tried to collect all that has been written on the subject of my study. It seemed to me that it would be very interesting for the reader to have thus before him all the pieces of evidence, with infinite variety of narration, frequent contradiction, and often instructive repetitions. I thought it best to give the actual works of the authors quoted: I distrusted even the most conscientious analyses; in my bibliographic research I have repeatedly seen the affirmations of an author changed to negation by a series of translations and anal- yses. Besides, summarizing and analytical chapters rest the mind of the reader; but each of the facts given there finds its proof in the preceding extracts.

In the second part my personal experiments are recorded. The titles of the chapters show the order in which I planned their exposition. A glance at the table of contents indicates that after studying directly the influence of changes in barometric pressure, I have devoted a few chapters to new researches on the physio- logical action of carbonic acid, on asphyxia, and on blood gases. The reader will see in perusing these chapters that I have not wandered as far from my subject as this mere statement of topics might imply; the numerous references to this part of my book that I make in my conclusions give evident proof of this fact.

In reporting my experiments, which number about 670, I have used the enumerative method; all those which seem to me inter- esting have been reported at length. This method has two advan- tages: first, it furnishes proof of all the conclusions, and second, it sometimes permits the reader to find in the account of the experi- ments what the author did not see there himself. Summaries added to each chapter facilitate rapid perusal of the results obtained. Finally I call attention to the fact that on each point the experi- ments are listed according to their date of performance; one can thus take account of observations which escaped attention at the beginning of the research, of improvements made by the experi- menter, and consequently of the constantly lessening number of causes of errors.

Finally the third part is entitled: Recent Data, Summary and Conclusions. I first discuss the history which in the first part I carried down only to my own work. Then I draw conclusions from my whole series of researches. It will be seen that here my agree- ment with M. Jourdanet could not be carried out literally, and that I could not keep from trespassing somewhat on the domain reserved for him.

The third and last chapter, whose title is General Conclusions,

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contains only three pages. May this temperance in the summary bring me pardon for the eleven hundred and fifty pages which I thought necessary in order to bring the reader to this point! I leave to others the delicate task of deciding whether this antithesis deserves criticism or praise. I shall merely remind the reader, pleading at last extenuating circumstances, that since the Institute did me the honor in 1875, on the recommendation of the Academy of Sciences, of bestowing upon my work the grand biennial prize,3 it seemed to me that it was my duty to spare myself neither time nor trouble to make the publication of my work more worthy of this great award.

Before finishing this preface, I must thank M. Grehant and M. Dastre, my assistants in the chair of physiology of the Faculty of Sciences, Dr. Jolyet, assistant director of the laboratory, and M. Paul Regnard, assistant in the course, who aided me in my research with affectionate devotion.

P:B October, 1877.

1 See my Lessons on the Comparative Physiology of Respiration; Paris, 1870, pages 121-130.

2 Paris. C>. Masson. 1875. Second edition. 1876.

3 This award of the first order is given every other year, according to the terms of the con- stitutional decree, "to the work or discovery which has made the greatest contribution to the honor or the service of the country" in the last ten years, in rotation for each of the branches of human learning represented by the five classes of the Institute.

The triennial prize, by the decree of April 14, 1855, was decreed to M. Fizeau, in 18o6; it was triennial only once, and by the decree of December 22, 1860, at the request of the Institute, it became biennial, and since then the awards have been as follows:

To Thiers (Academie franQaise), 1861.

To Jules Oppert (Academie des inscriptions et belles-lettres), 1863.

To Wurtz (Academie des sciences) , 1865.

To Felicien David (Academie des beaux-arts), 1867.

To Henri Martin (Academie des sciences morales et politiques) , 1869.

To Guizot (Academie franQaise), 1871.

To Mariette-Bey (Academie des inscriptions et belles-lettres), 1873.

To Paul Bert (Academie des sciences), 1875.

To Chapu (Academie des beaux-arts), 1877.— (Editor's note.)

XIX

TABLE OF CONTENTS

First Part HISTORICAL

Page

Title I. Diminished pressure 3

Preliminary chapter: the lofty regions of the globe. 3

Europe "

Asia 10

America *2

15

Africa

Islands 15

Summary 16

Eternal snows ^

Living organisms 18

First chapter. Mountain journeys — 22

1. South America 22

The Conquerors. Acosta. De Herrera. Frezier. Bouguer.

La Condamine. Don Ulloa. A. von Humboldt. Wars of Inde- pendence. S. Haigh. Miers. Caldcleugh. Schmidtmeyer. Brand. De la Touanne. Temple. Bollaert. D'Orbigny. Poep- pig. Boussingault. Meyers. Ch. Darwin. Smyth and Lowe. Arch. Smith. CI. Gay. Von Tschudi. De Castelnau. Weddell. De Saint-Cricq. Gillis. Lloyd. Grandidier. Burmeister. Markham. Martin de Moussy. Mateo Paz Soldan. Guilbert. Pellegrino Strobel. Focke and Mossbach. Pissis. Wisse. J. Remy. Steubel.

2. Central and North America 59

Wafer. Dollfus and 'de Montserrat. Burkhardt. Elliotson. Glennie. Gros. Truqui and Craveri. Laverriere. Scientific Commission of Mexico. Von Muller. Fremont. Gunnison. Hines. Williamson. Coleman.

3. Etna 69

Bembo. Filoteo. Fazello. Borelli. Riedesel. Demeunier. Houel. Delon. Dolomier. Spallanzani. Ferrara. De Gour- billon. De Forbin. De Sayve. XXI

Page

4. Peak of Teneriffe 73

R. Boyle. Edens. Feuillee. Glas. Riche and Blavier. Von Humboldt. Cordier. L. de Buch. Dumont d'Urville. Le Guillou. Ch. Sainte-Claire Deville. Itier. Madame Murray.

5. Alps _' 77

Bourrit. Laborde. De Saussure. Beaufoy. Forneret and Dor- theren. De Lusy. Van Rensselaer. Hamel. Clissold. Clark and Sherwill. Hawes and Fellowes. Auldjo. Meyer. Parrot. Vincent and Zumstein. Molinatti. Hugi. H. Cloquet. Martin Barry. Atkins. Mademoiselle d'Angeville. Desor. G. Studer. Spitaler. Forbes. Lepileur. Bravais. Martins. Chomel and Crozet. Tyndall. Tyndall and Frankland. Pitschner. Piachaud. Lortet and Marcet. Durier. A. Tissandier. Hardy. Tuckett. Kennedy. C. Grove. Visconti. Gamard. Joanne. Ormsby. H. Russell.

6. Pyrenees 120

Rob. Boyle. Dralet. Ramond. Arbassiere. Cordier and Neer- gaard. Parrot. De Franqueville. Russell-Killough. Le Mula- hacen.

7. Caucasus. Armenia. Persia 123

Engelhardt and Parrot. Kupffer. Sjorgrun. Radde. Douglas Freshfield. Gardiner.

Rob. Boyle. Tournefort. Parrot. Chodzko. Radde and Siev-

ers. Hamilton.

Taylor Thomson. R. F. Thomson.

8. Central Asia i 128

Marco-Polo. Hiouen. Tsang. Chinese Itinerary. Missionaries.

S. Turner. Th. Hardwicke. Moorcroft. Fraser. Webb. Gerard Brothers. Johnson. V. Jacquemont. Wood. Burnes. Father Hue. Hoffmeister. Th. Thomson. Dalton Hooker. Robertson. Mistress Hervey. Oliver. Cheetam. Semenof. Schlagintweit Brothers. Godwin-Austin. The Pundits. The Mirza. Hayward. Faiz Buksh. Henderson. Hume. Drew.

9. Africa 161

Burton. Mann. Rebmann. De Decken. New.

10. Volcanoes of the Pacific 162

Low. Brooke. Braddel. Rutherford Alcock. Gubbins. Jef- freys. Byron. D. Douglas. Loenenstern. Wilkes.

Chapter II. Balloon Ascensions 171

Charles and Robert. Leullier-Duche. Testu-Brissy. Blanchard. De Lalande. Robertson. Garnerin. Zambeccari. Biot and Gay- Lussac. Andreoli. Beaufoy and Sadler. Madame Blanchard. Eug. Robertson. Green. Comaschi. Hobard. Barral and Bixio. Welsh. Glaisher. Croce-Spinelli and Sivel. Simons.

Chapter III. Theories and Experiments 195

Acosta. Fr. Bacon. Academy del Cimento. Van Musschenbroeck. Robert Boyle. Huyghens and Papin. Beale. Veratti. Cigna. Darwin. Borelli. Bouguer. Ulloa. Haller. De Luc. Bourrit.

XXII

Page De Saussure. Fodere. Halle and Nysten. Courtois. Legallois. Dralet. Gondret. Fraser. Govan. Gerard Brothers. Hodgson. H. Cloquet. Clissold. Roulin. J. Davy. Rostan. Cunningham. Burdach. Poeppig. Boussingault. De Humboldt. Junod. Magen- die. Favre. Barry. Martins. Rey. Tschudi. A. Smith. Hill. Maissiat. Flechner. Brachet. Castel. Vierordt. Lepileur. A. Vogt. Father Hue. Przevalski. Pravaz. Payerne. Marchal de Calvi. Speer. Mayer-Ahrens. Lombard. Valentin. Heusinger. Giraud-Teulon. F. Hoppe. Fernet. Longet. Gavarret. Duval. Lombard. Martins. Guilbert. Jourdanet. His discussions with Coindet. Cavaroz. Tardieu. Foley. Liguistin. Leroy de Meri- court. Gavarret. A. Dumas. Scoutetten. Kaufman. Coindet. Gavarret. Von Vivenot. Flemeing. Bouchard. Beclard. Hudson. Piachaud. Lortet. Marcet. Forel. Clifford-Albutt. Dufour. Javelle. Tyndall. Durier. Russell-Killough. Mistress Hervey. Henderson. Drew. Burton. Hunt. Jaccard. Armieux. Gosse. Jourdanet. The Academy of Medicine in 1875. Virlet d'Aoust.

Chapter IV. Summary and Criticisms 315

1. Conditions of the appearance of mountain sickness 315

2. Symptoms of mountain sickness 328

3. Theoretical explanations 335

Pestilential exhalations. Electricity. Lack of oxygen in the

air. Fatigue, cold. Theories of M. Lortet and M. Dufour. Lessening of the weight supported by the body. Escape of blood gases. Expansion of intestinal gases. Relaxing of the coxo-femoral articulation. Other mechanical actions. Excess of carbonic acid in the blood. Theory of de Saussure and Martins. Theory of M. Jourdanet.

Title II. Increased Pressures 353

Chapter I. High pressures 355

1. Diving bells 355

Sturmius. Halley. Spalding. Brize-Fradin. Hamel. Colladon.

2. Apparatuses constructed in the Triger method 358

Papin. Triger. Trouessart. De la Gournerie. Blavier. Pol and Watelle. Comte. Bouhy. Brunei. Cezanne. Regnauld. Babington and Cuthbert. Francois, Bucquoy. Foley. Nail. Hermel. Limousin. Bayssellance. Gallard. Triger. Barella. Eads. Bauer. Malezieux. Unpublished information.

3. Divers with suits 390

Borelli. Halley. Leroy de Mericourt. Denayrouze. Gal. Sampadarios.

Chapter II. Low pressures 411

Junod. Tabarie. Pravaz. Milliet. Sandahl. Tutschek. G. Lange. Vivenot. Freud. Elsasser. Panum. G. Liebig. Mayer. Marc.

XXIII

Page

Chapter III. Theoretical Explanations and Experiments 440

Borelli. Musschenbroeck. Haller. Achard. Brize-Fradin. Halle and Nysten. Poiseuille. 'Maissiat. Hervier and Saint-Lager. Pravaz. Pol and Watelle. A. Guerard. Milliet. Eug. Bertin. Hoppe. Francois. Bucquoy. Hermel. Foley. Caffe. Babing- ton and Cuthbert. Sandahl. Tutschek. Vivenot. G. Lange. Elsasser. Panum. G. Liebig. Gavarret. Leroy de Mericourt. Bouchard. Gal.

Chapter IV. Summary and Criticisms 489

1. Physiological action of compressed air.

A. Phenomena due to compression.

B. Phenomena due to decompression.

2. Theoretical explanations.

A. Phenomena due to compression. Physico-mechanical explanations. Chemical explana- tions.

B. Phenomena due to decompression.

Second Part EXPERIMENTS

Chapter I. Chemical conditions of the death of animals subjected to

different barometric pressures in closed vessels 505

Subchapter 1. Pressures below one atmosphere 507

1. Experimental set-up 507

2. Experiments : 513

A. Experiments on birds 513

B. Experiments on mammals 542

C. Experiments on cold-blooded animals 550

3. Conclusions 552

Subchapter 2. Pressures above one atmosphere 552

1. Experimental set-up 552

2. Experiments 555

A. Compressions with ordinary air 555

B. Superoxygenated air; pressures between one and

two atmospheres 560

C. Compressed air at very high pressures.

Lethal action of oxygen 565

D. Compression with air of low oxygen content 570

E. Compression with superoxygenated air 571

F. Compression with ordinary air; elimination of carbonic acid 574

3. Conclusions 577

Subchapter 3. Summary and conclusions 578

XXIV

628

Page Chapter II. Gases contained in the blood at different barometric

pressures ' 581

Subchapter 1. Operative methods and experimental discussion __. 581

Subchapter 2. Blood gases under pressures less than one atmos- phere 594

1. Experimental set-up 594

2. Experiments - 600

Subchapter 3. Blood gases under pressures greater than one

atmosphere 615

1. Experimental set-up 615

2. Experiments - 618

Subchapter 4. Blood gases in asphyxia compared to decreased pressure ■-—

Subchapter 5. The quantity of oxygen which the blood taken from the vessels can absorb at different barometric pressures 641

1. Pressures lower than one atmosphere 643

2. Pressures greater than one atmosphere 654

Chapter III. Phenomena presented by animals subjected to pressures

less than one atmosphere 660

Subchapter 1. Symptoms of decompression 661

1. Respiration _' 666

2. Circulation 669

3. Digestion 672

4. Nervous and muscular effects 673

5. Nutrition 675

Chemical phenomena of respiration. Urinary excretion. Sugar of the liver and blood, glycosuria. Temperature. Development.

6. Lower limit of pressure 685

7. Death 687

Subchapter 2. Comparison of the phenomena of decompression

with those of asphyxia in closed vessels 689

Subchapter 3. Means of warding off the symptoms caused by de- compression 694

Chapter IV. Action of compressed air on animals 709

Subchapter 1. Toxic action of oxygen at high tension 709

2. The diminution of oxidations caused by oxygen poisoning 743

3. Aquatic or invertebrate animals 751

Subchapter 2. Action of compressed air at low pressures - 754

1. Short stay in compressed air 756

A. Experiments made upon myself 756

XXV

Page

B. Production of urea; experiments on dogs 764

C. Chemical phenomena of respiration 765

D. Pulmonary capacity 768

E. Intra-pulmonary pressure 771

F. Arterial pressure 773

2. Prolonged stay in compressed air 775

Chapter V. Influence of changes in barometric pressure on plant life 780

Subchapter 1. Pressures less than one atmosphere 782

1. Germination ._ 782

2. Vegetation 787

Subchapter 2. Pressures above one atmosphere 788

1. Germination 788

A. High pressures with air of low oxygen content 792

B. Normal pressure; superoxygenated air 793

C. Low pressures; superoxygenated air 794

2. Vegetation 797

Subchapter 3. Summary 798

Chapter VI. Action of changes in barometric pressure on ferments,

poisons, viruses, and anatomical elements 799

Subchapter 1. Fermentations by organisms 800

1. Putrefaction 800

A. Meat 800

B. Blood 817

C. Eggs 819

2. Coagulation of milk 820

3. Alteration of the urine 823

4. Brewer's yeast 826

5. Wine ferments 827

6. Molds 831

Subchapter 2. Diastatic fermentations 834

1. Saliva and diastase 835

2. Pepsin 837

3. Inversive ferment of yeast 838

4. Myrosin 838

5. Emulsin 839

Subchapter 3. Action of oxygen at high tension upon anatomical

elements 839

Subchapter 4. Use of oxygen at high tension as an experimental

method 842

1. Dry rot of fruit 843

2. Ripening of fruits 844

3. Venoms 845

4. Viruses 846

XXVI

Page

A. Vaccine 846

B. Glanders 847

C. Anthrax 847

Subchapter 5. Summary 849

Chapter VII. Effects of sudden changes in barometric pressure— . 852

Subchapter 1. Effects of sudden increases in pressure 852

Subchapter 2. Effects of sudden decreases in pressure beginning

with one atmosphere 853

Subchapter 3. Effect of sudden decrease in pressure beginning

with several atmospheres 859

1. Decompression without interruption 859

A. Experiments on sparrows 859

B. Experiments on rats 861

C. Experiments on rabbits 861

D. Experiments on cats 861

E. Experiments on dogs 863

2. Slow decompression in several stages 874

3. Summary and conclusions from the preceding experiments 878

Subchapter 4. Prophylaxis and treatment of the symptoms of sud- den decompression 890

Subchapter 5. Summary 895

Chapter VIII. Various questions 896

Subchapter 1. Action of carbonic acid on living beings 896

1. Lethal tension of carbonic acid in ambient air 896

2. Lethal concentration of carbonic acid in the blood 899

3. Accumulation of carbonic acid in the tissues 910

4. Symptoms and mechanism of carbonic acid poisoning 914

5. Action of carbonic acid on lower living beings 924

6. Summary and conclusions 927

Subchapter 2. Asphyxia — 928

Subchapter 3. Observations on the gases of the blood 935

Third Part RECENT DATA, SUMMARY AND CONCLUSIONS - 947

Chapter I. Decreased pressure 949

Subchapter 1. Observations, theories, and recent discussions 949

Bouchut. Chabert. Dufour. Forel. Thorpe. Tempest An- derson. Calberla. Ward. Vacher. Croce-Spinelli, Sivel and G. Tissandier. Stoliczka. Campana. Jourdanet.

XXVII

Page

Subchapter 2. Summary and practical applications 980

1. Aeronauts 981

2. Mountain travellers 991

3. Dwellers in high places 998

4. Animal and plant life at high elevations 1005

5. Medical applications 1006

Chapter II. Increased pressure 1009

Subchapter 1. Observations, theories, and recent discussions 1009

1. High pressures 1009

Guichard. Heiberg.

2. Low pressures. Medical apparatuses 1014

J. Pravaz. G. Liebig. Leonid Simonoff.

Subchapter 2. Summary and practical applications 1021

1. High pressures 1021

2. Low pressures^ _i 1024

3. Sudden decompression 1027

4. Practical applications. Therapeutics and hygiene 1027

5. Conclusion from the point of view of general natural history 1032

Chapter III. General conclusions 1036

Addenda I. Relations between heights and barometric pressures 1039

II. The new work of Dr. Mermod 1041

Index — 1045

XXVIII

Fig.	1.
Fig.	2.
Fig.	3.
Fig.	4.
Fig.	5.
Fig.	6.
Fig.	7.
Fig.	8.

LIST OF ILLUSTRATIONS

Page

Lortet. Respiratory tracing taken at Lyons (200 meters) 112

Lortet. Respiratory tracing taken at the summit of Mont

Blanc (4810 meters), after resting an hour 112

Cupelain: Chamounix (1000 meters) - 113

Grands-Mulets (3000 meters) at midnight, half an hour before

starting H3

Summit of Mont Blanc (4810 meters) 113

The construction of a bridge pier by the use of caissons 369

Diver equipped with the Denayrouze regulator, complete suit 391 Diver equipped