432 METABOLISM, NUTRITION, AND DIET 



behind, sugar appears in the urine when carbohydrates are eaten, but not 

 otherwise. Nor is it necessary that the remaining portion of the gland be in 

 its normal situation. Successful grafts of pancreas under the skin of the 

 abdomen or elsewhere will prevent the appearance of sugar in the urine and 

 the other symptoms. If, however, the graft be subsequently removed, the 

 sugar in the urine and the other symptoms reappear, and the experimental 

 disease proceeds to a rapidly fatal issue. 



The symptoms produced by total extirpation of the pancreas do not de- 

 pend upon the loss of the pancreatic juice proper to the organism. This 

 secretion may be diverted from the intestine through a pancreatic fistula 

 without the production of diabetes. Moreover, Hedon and Thiroloix have 

 rendered the acini of the gland functionally inactive, and ultimately de- 

 stroyed them, by the injection of paraffin or other substances into the duct 

 of Wirsung, without the supervention of diabetes. 



These experiments have shown that the ordinary secreting cells degener- 

 ate and the islands of Langerhans increase in size, leading to the conclusion 

 that these are the structures that produce a special internal secretion which 

 influences or controls carbohydrate metabolism in the body. Whether this 

 hypothetical substance is necessary to the dehydration and synthesis of dex- 

 trose in the body or whether it is necessary to the complete oxidation of carbo- 

 hydrate is at present a matter of inference. 



The Reproductive Glands. The ovary and the testes are un- 

 doubtedly concerned with metabolism in the body. It has been shown 

 repeatedly that extracts of the testes when injected into the system lead to 

 increased vigor, both of the muscular and of the nervous systems. Ergograms 

 show an increase in muscular power. Spermin isolated from the testes is 

 claimed by its discoverer to produce the beneficial effects described. The re- 

 moval of the testes in domestic animals is followed by an entire change in the 

 character of the development of the animal, especially in the so-called second- 

 ary sexual characters. Such animals show less vigor and muscular power. 



The removal of the ovaries in women, through surgical operation, has 

 resulted in very marked nervous symptoms. These symptoms are reduced 

 or entirely disappear on grafting a portion of the gland, and the disturbed 

 menstruation following ovariotomy becomes regular again. Experiments by 

 Loewy and Richter indicate that oxidations in the body are greatly increased 

 on feeding ovarian extract to ovariotomized animals. 



There are other organs whose function is still obscure but in which 

 the indirect evidence points to an influence on metabolism at one stage or 

 another of the existence of the animal body. Enough has been given here 

 to show that the interrelation of the organs is extremely complex in so far as 

 the metabolism is concerned. It is not enough simply to know the foods and 

 their composition. The whole complex of intermediary metabolism and 

 their influence must constantly be taken into consideration. 



