Theories and Experiments 305 



tions which give rise to them? Especially what are the causes which 

 give rise to the disease of mules known by the name of trembladera? 

 Are the domestic llamas and those used as beasts of burden equally 

 subject to this disease? 



20. Is the mortality of certain animals (cats, for example), caused 

 by their sojourn in very lofty places, an established fact or not? And 

 if the fact is established, what are the symptoms which precede death, 

 and what are the probable causes of this mortaltiy? 



21. Are there means of awarding off the soroche, and if there are, 

 what are they? Has anyone tried, for example, in Peru, as in Styria 

 and the Tyrol, the ingestion of small doses of arsenic to prevent the 

 fatigue of the ascent of mountains? Study particularly in this connec- 

 tion the effects of the plant known as cuca or coca, either chewed or 

 taken in an infusion, which they say has a remarkable prophylactic 

 power. 



22. What are the means employed with the greatest success in 

 checking or lessening the symptoms produced by the soroche, either in 

 man or in the animals? (P. 113-117.) 



As I said at the beginning of this first part of my work, I 

 shall not discuss in this historical section any researches which 

 rely upon the results of my own investigations or which oppose my 

 conclusions. My discussion of them will naturally take place in 

 the third part. 



And for this reason I shall say nothing of the book recently 

 published by M. Jourdanet, 140 in which he repeats, develops, and 

 supports by new proofs taken from the study of altitudes over the 

 whole earth the opinions suggested to him by observation of the 

 diseases of Upper Mexico. I shall borrow from this immense work 

 only the account of an important experiment in which appears 

 the first attempt made to study chemically the degree of the 

 anoxemia: 



I decided to devote myself to this work of analysis about the end 

 of 1864. I found assistance— very worthy of special mention in this 

 book — in the laboratory and the cooperation of M. Romuald Zamora, 

 a Spanish gentleman, who studied the sciences in his hours of leisure. 

 I analyzed the blood of three rabbits by means of carbonic oxide, fol- 

 lowing the specifications given by M. Claude Bernard. I found an 

 average of oxygen which was very low, but not enough to justify one 

 in feeling authorized to make really legitimate general conclusions. I 

 also felt hesitant because of a consideration which I thought exceed- 

 ingly important; namely, that one could always ask himself whether 

 these same animals would not have given this same quantity of oxygen 

 at lower levels. In fact, differences in amount found in my previous 

 analyses of blood prove that the proportion of this gas is an individual 

 peculiarity, at least within certain limits. It seemed to me after that, 

 that this interesting point cannot be indisputably decided without a 

 double analysis of the blood of the same animal, drawn first at normal 



