Theories and Experiments 241 



of the body, there is at the same time rarefaction of the air entering 

 our lungs, and consequently decrease in the quantity of oxygen nec- 

 essary for the normal accomplishment of hematosis. 



In 1853, Speer, 76 an English physician, published a special work 

 on the nature and causes of mountain sickness. He begins by tell- 

 ing that he himself, on the main peak of Mont Blanc, began to feel 

 the following symptoms when he had reached 9000 feet: 



Congestion in the head, throbbing of the carotids, palpitations of 

 the heart, distaste for food. At 10,000 feet, he felt a constriction of the 

 chest, and shortly after, the taste of blood in his mouth, which was 

 caused by a slight exudation from the gums. 



He then reviews the different explanations suggested, dwelling 

 on that of Brachet, which he finds "too exclusive". To his mind, 

 the great fatigue of the muscles is caused by "the congestion of 

 blood which follows their repeated contractions", and as for the 

 other symptoms of mountain sickness, they are due chiefly to "the 

 irregularity of the circulation, with congestion of the brain and 

 the abdominal viscera". 



The following conclusions indicate clearly the author's line of 

 thought: 



Mountain sickness is characterized by the following symptoms, 

 the union of all of which, however, is only rarely seen, if ever, in 

 the same person: vertigo, headache, drowsiness, dyspnea, constriction 

 of the chest, palpitations, tendency to syncope, oozing of blood from 

 the mucous surfaces, increased rapidity of the pulse, anorexia, nausea 

 and vomiting, thirst, feverish tongue, muscular pains, sensation of 

 extreme weakness in the lower limbs, general prostration. 



These symptoms should be attributed to three causes: gradually 

 increasing congestion of the deep portions of the circulatory apparatus; 

 increase of venous plethora of the blood; loss of equilibrium between 

 . the outer air and that of the gases present in the intestine. 



These determining causes of mountain sickness are themselves the 

 result of the considerable and rapid change in the pressure and the 

 temperature of the atmosphere. 



The next year, Dr. Conrad Meyer-Ahrens," a physician at 

 Zurich, devoted to the study of the symptoms of decompression 

 a long work far more important than that of Speer. 



This memoir is composed of two parts; in the first (p. 1-99) 

 the narratives of a great many travellers are reported with details; 

 the second summarizes the symptomatology (p. 99-123) and indi- 

 cates the etiology (p. 123-136), the prophylaxis and treatment (p. 

 136-139) of mountain sickness. 



In the preceding chapters, we have given all the data quoted 



