PARTS AND FEATURES 



samples of sperm oil and E. K. Marshall kindly determined for me their 

 power for absorption of carbon dioxide. One hundred cubic centime- 

 ters of each dissolved respectively 92.8 and 94.6 cc. of carbon dioxide. 

 This was left standing for 72 hours and the samples then refused to ab- 

 sorb more carbon dioxide, indicating that none of the original gas taken 

 up had suffered change. One hundred cc. of water, alcohol, and petro- 

 leum will absorb respectively 54.6, 230, and 82 cc. of carbon dioxide; 

 so it is seen that these experiments do not show that sperm oil is re- 

 markably solvent of this gas. It should be pointed out, however, that 

 the question is by no means settled. The samples used were of old 

 sperm oil which had been altered by the action of the free fatty acids 

 which it contains in considerable amount. The experiment should be 

 repeated with -fresh material, and under pressures increasing to one ton 

 to the square inch. 



In abandoning this topic it should again be emphasized that we know 

 nothing whatever about any physiological process, other than for the 

 conservation of heat, which the fatty tissues of aquatic mammals may 

 have. All that is now possible is to advance tentative and unsupported 

 hypothesis as a basis from which to work. 



DIGESTIVE SYSTEM 



The digestive system of pinnipeds and cetaceans at least is called upon 

 to furnish an unusual quantity of raw material for the production of 

 both blood and fat ; but it is difficult to know which features constitute 

 phylogenetic inheritances from terrestrial ancestors and which may have 

 been developed by an aquatic life. The stomach of the Cetacea, both 

 Odontoceti and Mysticeti, is very complicated and with numerous di- 

 visions. It is usually stated that most forms have four of these with a 

 fifth dilation of the duodenum, but ziphioid whales may have "9, 10, 

 even 13 or 14" divisions, according to Beddard, quoting other authors, 

 and in the latter group the structure suggests that the usual first division 

 may be missing. In this character of complexity the cetacean stomach is 

 comparable to that of ruminants, but there are fundamental differences 

 and their resemblances are probably attributable to convergence rather 

 than to relationship. Apparently conditions may be interpreted as fol- 

 lows. 



The typical porpoise stomach consists of a relatively simple division 

 which appears to be a dilation of the esophagus. It communicates by a 

 passage in its upper wall with the second division, whose walls are 

 heavily plicated and of great thickness. It is here that the gastric juices 



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