176 



astinal surfaces of both lungs, the entire viscus was adherent to 

 surrounding structures. Nowhere was there any vestige of a pleural 

 cavity, though the pericardial cavity was present as in other mammals 

 and showed no pathological change. 



Moreover the tissue uniting lung with parietes was elastic in 

 nature, permitting necessary respiratory movements of lung, It was 

 of uniform density and thickness throughout, and was also present 

 between the rudimentary lobes into which the lung is subdivided. 

 I was interested to note this peculiar modification in the elephant. 

 Goldscbmidt's paper conclusively shows that the pleural cavity 

 is normally absent in the animal (7). But at the time my invest- 

 igations were carried out I was unaw^are of Goldschmidt's work. 



In view of the fact that previous observers have often disagreed 

 on the question of presence or absence of the pleural cavity in the ele- 

 phant, and because these observations of mine were made quite apart 

 from those of Goldscbmidt and yet confirm his work in every par- 

 ticular I have thought it advisable to publish them. 



Harrison (1), Vulpian and Phillipeaux (2), Miall and Green- 

 wood (3) among others have all described the absence of the pleural 

 cavity in elephants. Beddard (4) notes its absence in the elephant 

 and the tapir. 



Perhaps the most remarkable instance in which the presence 

 was asserted is that of Vasse who shot a wild African example and 

 investigated the condition at once. As, however, the views of different 

 observers are discussed in full by Goldschmidt, it is unnecessary to 

 give the subject further consideration here. Suffice it to say that 

 those investigators who asserted the presence of the cavity were 

 misled by a hurried dissection or did not have a fair chance of making 

 correct observations. 



Of these latter Morrison Watson (5) is one. Although he did not 

 definitely state that a pleural cavity is present, the following sentence 

 occurs in his description of the thoracic viscera. 



"The arrangement of the pleural sacs could not be determined 

 because of their lacerated condition. The pleura did not separate 

 the lobes but passed continuously over them." From this I gathered 

 that Watson believed the pleural cavity was present and I know 

 that he dissected at least one elephant while he was in Edinburgh 

 and another after he came to Manchester. 



