THE ACTIVE FORCES OF LIVING ORGANISMS 63 



heights is the oft-occurring and frequently regular 

 pause between the inspiration and expiration, as 

 though for a brief interval the need of fresh oxygen 

 were not felt by the organism, and life were, so to 

 speak, momentarily suspended. This is very clearly 

 shown in respiratory tracings taken from two soldiers, 

 Sarteur and Solferino. The case of Sarteur is of 

 peculiar interest, since his respiratory frequency fell 

 on one occasion to as low as eight per minute, although 

 he was one of the strongest men of the party, and on 

 being waked ate with appetite and felt well. These 

 tracings were taken at the Queen Margaret's hut, and 

 very remarkable is the difference in respiratory 

 frequency, that of Sauteur being eleven and that of 

 Solferino twenty-one per minute, although they were 

 of the same age, almost the same size, had at the 

 time eat^n the same kind of food, and had walked the 

 same distance. One sees from this example the 

 importance of the personal or nervous factor. 



The respiratory frequency of a dog, subjected by Experi- 



. , ment to 



Mosso to the inhalation of air contammg 16 "7 per demon- 

 cent, of carbonic acid, rose from twelve per minute effect of 

 to as much as forty and forty-four.* Unfortunately, add on'the 

 there is no evidence in this case of the depth of the tory'move- 

 respiratory movements; but if carbonic acid be, as ™®°*^' 

 is generally held to be the case, a stimulus to the 

 respiratory centre, the more rapid elimination of it 

 at high altitudes would naturally lead, as we have 

 said, to shallower breathing, and this in turn would 

 * Mosso, loc, cit,, p. 416. 



