488 



SCIENCE 



[N. S. VoL-XXV. No. 639 



The entire stomach or the greatest part of 

 it has been removed in animals and man 

 without interfering with digestion and nu- 

 trition. Of the small intestines large parts 

 have been resected without serious conse- 

 quences. In human beings the largest part 

 removed measured, I believe, over three 

 meters, and Erlanger and Hewlett have 

 studied the metabolism of dogs seven or 

 eight months after the removal of seventy 

 or eighty per cent, of the movable part of 

 the small intestines. Three fourths, then, 

 of the small intestines are almost a luxury 

 to the body. We need, not, perhaps, speak 

 of the fact that surgeons have removed 

 large parts of the colon without ill effects. 

 From the present attitude of bacteriolo- 

 gists and physiological chemists towards 

 the activities of the large intestines one is 

 led to believe that the body might do best 

 without any part of that organ. Be this 

 as it may, it is quite sure that the digestive 

 canal is provided with a good deal more 

 structure than is required for the main- 

 tenance of its function. 



Here we shall discuss briefly also the 

 luxurious provision of the alimentary canal 

 with digestive ferments. There are two 

 proteolytic ferments: pepsin and trypsin, 

 to which we may add also erepsin, a fer- 

 ment found by 0. Cohnheim in the mucous 

 membrane of the small intestines and 

 which is said to be capable of splitting 

 albumose into amino acids. There are two 

 amyloljrtie ferments: the ptyalin of the 

 salivary glands and the amylopsin of the 

 pancreas. As to lipolytic ferments, the 

 steapsin of the pancreas i& not the only one 

 of that kind which reaches the contents of 

 the digestive canal. Thus several investi- 

 gators have recently confirmed the state- 

 ment of Volhard that the fundus of the 

 stomach secretes a lipase which is capable 

 of splitting emulsified fat. Lipase is con- 

 tained also in the liver and in the bile. 



Now there are a number of experiments 

 and clinical facts which go to show that 

 digestion can continue in normal fashion 

 even if one half or at least a good part of 

 these ferments are eliminated from the 

 digestive tract. Older and recent experi- 

 ments have established the fact that the 

 removal of the salivary glands has no effect 

 upon the digestion. We know, on the other 

 hand, that after removal of the pancreas 

 or in cases of isolated destructive diseases 

 of this organ the digestion of carbohy- 

 drates is not disturbed. Normally, there- 

 fore, there is a superabundance of amylase 

 in the digestive canal. As to the proteo- 

 lytic ferments, we have already mentioned 

 that the complete removal of the stomach 

 does not disturb digestion. Furthermore, 

 in cases of achylia gastrica, in which the 

 stomach secretes neither hydrochloric acid 

 nor pepsin, the proteid digestion is appar- 

 ently normal. On the other hand, we know 

 that the elimination of the pancreas does 

 not affect palpably the proteid digestion. 

 With regard to lipase, clinical pathology 

 was teaching that in cases of disease of the 

 pancreas the stool contained fat, which 

 would seem to indicate that in the absence 

 of the pancreatic lipase no other lipolytic 

 ferment was present in sufficient quantity 

 to split completely the ingested fat. How- 

 ever, in a very recent study of Umber and 

 Brugsch it was shown that the fat-split- 

 ting function is carried on even in the ab- 

 sence of the pancreas in a normal way. 



We are then surely justified in claiming 

 that the various digestive ferments exist in 

 the alimentary canal in quantities far 

 above the necessities for the digestion of a 

 normal amount of food. 



All the numerous organs and complex 

 tissues which we have just passed in review 

 are built on a plan of great luxury. Some 

 organs possess at least twice as much tissue 

 as even a maximum of normal activity 



