258 Historical 



the muscular fatigue which we are discussing when they had hardly 

 gone beyond a fourth of the atmospheric pressure, we shall see that 

 this phenomenon appeared when the thigh was still supported by a 

 weight of 17 kil. 734 gm. We do not understand why a member, 

 which may weigh at most 15 pounds, would have so little respect for 

 the 21 pounds surplus which it would drag along in its fall. (P. 89.) 

 The real reason, according to M. Jourdanet, is expressed thus: 



This phenomenon appears when the blood, incompletely oxygen- 

 ated, causes the contractile power of the muscular fiber to be 

 considerably diminished. The abdominal member then refuses to carry 

 out its normal functions and warns by pain that the task is beyond 

 its powers. The same thing would happen to the other muscles of 

 the body, if one required of them the exaggerated efforts which ascent 

 demands from the muscles of the thigh. (P. 89.) 



Summarizing: 



The symptoms of the famous mountain sickness: vertigo, swoon- 

 ing, vomiting, — what do they amount to but cerebral anemia, for 

 want of the stimulus of arterial oxygen; congestion of the venous 

 system, and especially the portal vein and the liver; but, above all, 

 enervation of the muscular fiber for the same reason. 



Always and everywhere: lack of the normal quantity of oxygen 

 in the circulation of the arterial blood. (P. 90.) 



Most of the book is devoted, as its title indicates, to the study 

 of the diseases of Mexico. Everywhere there M. Jourdanet finds 

 predominant the effect of this anemia of a special type, "result of 

 an imperfect respiratory endosmosis". It is indeed, as he says 

 clearly in his subsequent works, this strange syndrome which, 

 awakening his medical shrewdness, caused him to reflect upon the 

 conditions harmful to respiration and metabolism presented by a 

 prolonged sojourn on the lofty plateaux of Anahuac. 



I shall merely quote the following passage because it offers a 

 sort of summary of this remarkable work, and because we find 

 in it a part given to the pressure as a mechanical agent, simply 

 assisting its chemical action: 



We have already seen the blood, feebly welcomed and lazily 

 expelled by the nervous centers, congesting the brain and the spinal 

 cord of weak persons, already injured by the climate. We shall 

 mention the disturbances of more than one sort of the alimentary 

 canal, several of which are due to the circulatory slackening and to 

 the capillary congestions of the intestinal venous system. The uterus 

 has attracted our attention by phenomena of the same nature. We 

 shall take the opportunity to say here that pulmonary congestions 

 are frequent in Mexico and too often are fatal. Finally, more 

 frequently than all the other organs, the liver imbibes blood and from 

 this source draws countless symptoms, the unfortunate consequences 

 of which are frequently reckoned among the causes of death. 



