178 



of cartilage on the intrapulmonary bronchi at a greater distance than 

 one inch from the hilum. The conclusion inevitably formed from these 

 considerations was that the pleural cavity is normally absent in 

 elephants. It seemed advisable to investigate the conditions of 

 respiration in these animals to find out, if possible, the cause for such 

 a striking pecularity. 



It is often stated that the herbivora as a class differ from the 

 Carnivora in their respiration. In many of the former, there is, prac- 

 tically speaking, no diaphragmatic 

 respiration. Clinical examination of 

 respiration in elephants is not parti- 

 cularly appreciated by the animals 

 themselves. But as a result of inquiry 

 in one Indian and two African speci- 

 mens, it could be fairly definitely 

 shown that, contrary to my usual 

 findings among Ungulata, thoracic 

 respiration is negligible in these ani- 

 mals, and diaphragmatic action is 

 most important. These conclusions 

 were obtained by inspection and pal- 

 pation of the whole thoracic and ab- 

 dominal walls. The diaphragmatic 

 movement is intensified on taking a 

 deep inspiration which can be in- 

 duced by bringing the animal to its 

 pond to drink. In order to fill its 

 trunk with fluid it must inspire 

 deeply and the marked filling of the 

 flanks consequent on the descent of 

 the kidneys and other viscera is 

 plainly apparent. 



The important role played by 

 the diaphragm in respiration in this 

 animal is indicated by several ana- 

 tomical features. 

 1. The pillars of the diaphragm are enormously developed. 



Note. In view of the discrepancy of opinion on the modes of 

 respiration in animals, this subject it as present being investigated anew. 



Fig. 1. LoDgitudinal section of 

 lung of elephant showing the naked- 

 eye appearance of a laige intrapul- 

 monary bronchus (2.5 cm. diameter), 

 half natural size. The cut bronchi (B) 

 show longitudinal rugae of their mu- 

 cous membrane. Their wall is thicii 

 and of a firm consistence. (See fig. 2.) 

 The bloodvessels (A) exhibit a smooth 

 and less rosy appearance. 



