832 



SCIENCE 



[N. S. Vol. XXX. No. 780 



hastily, ill-considered diagnoses. If you find 

 the stomach not performing its functions 

 properly, your first thought will be to treat 

 the stomach, and yet such a procedure 

 might be useless, for the stomach may be 

 affected only secondarily. Among civilized 

 peoples there is constant communication 

 between separated individuals or communi- 

 ties, and the one is constantly influencing 

 the other. This influence may be performed 

 by the aid of two mediums : by the written, 

 spoken or telegraphed message, and by the 

 transmission of material things, such as 

 food, clothing, luxuries, or the thousand 

 things upon which our lives and actions a& 

 civilized beings depend. Thus, while mem- 

 bers of human society, we are not free, in- 

 dependent agents, each individual living 

 his life in isolation from his fellows. The 

 conditions are similar within a complex 

 organism like the human body; there too 

 no part is independent of the other parts. 

 The correlation between the various organs 

 of the body is a topic that is now looming 

 large above the horizon of physiological 

 discovery. There are two ways in which 

 one organ is capable of influencing another : 

 through nervous impulses and material 

 substances. Nervous influences have long 

 been recognized, but influence through the 

 action of material substances constitutes a 

 comparatively new subject. It is now 

 known of several organs that they manu- 

 facture chemical substances, which exert 

 characteristic physiological actions on the 

 cells of other organs. Thus the acid which 

 is formed by the glands of the stomach, 

 and is essential to gastric digestion, acts 

 upon the sphincter muscle at the plyorus 

 in such a manner as to cause it to relax 

 and open a passageway into the duodenum 

 for the digested gastric contents. Once ar- 

 rived within the small intestine, the acid 

 then causes a contraction of the sphincter, 

 which prevents the return of the chyme. 



But the duties of the acid are not yet com- 

 pleted. It proceeds to stimulate the epi- 

 thelium cells of the lining wall of the small 

 intestine and makes them produce a char- 

 acteristic substance, recently . discovered 

 and called secretin. This passes from the 

 cells into the blood-stream and takes two 

 paths : one to the pancreas, where it stimu- 

 lates the pancreatic cells to secrete their 

 characteristic digestive juice ; the other to 

 the liver, the cells of which are similarly 

 stimulated to produce bile. Any interfer- 

 ence with the production of acid in the 

 stomach may thus interfere with a whole 

 train of physiological processes which are 

 dependent upon it. Adrenalin, a peculiar 

 chemical substance formed by the adrenal 

 bodies, which in recent years has become 

 valuable to the physician because of its ex- 

 traordinary power of constricting blood 

 vessels, acts normally within the body upon 

 the whole sympathetic nervous system, 

 and thus influences the various important 

 organs supplied by the sympathetic nerves. 

 There is much reason for believing that 

 intimate relations exist, through the action 

 of chemical substances as yet obscurely 

 known, between the adrenal bodies, the 

 pancreas, the thyroid, the liver and per- 

 haps the heart and the stomach. But if the 

 mutual relations of normal organs are so 

 involved, it is easy to see how intricate the 

 situation may become M'hen an organ be- 

 comes diseased, and how difficult for the 

 physician may become the problem of lo- 

 cating, from the assemblage of symptoms, 

 the primary seat of the trouble. That the 

 problem is not necessarily hopeless of solu- 

 tion is demonstrated daily by clever diag- 

 nosticians. One can not help having a 

 profound admiration for the man who, 

 armed with an intimate knowledge of nerve 

 centers and nerve tracts, will from certain 

 obscure paralyses specify the exact spot in 

 the course of the tangled nervous system 



