THE SPLENO-PANCREATIC INTERNAL SECRETION. 415 



in turn, stimulate the adrenals through the communicating branches 

 between the cord and the ganglionic chain. 



What we might term the intrinsic functions of the pan- 

 creas have now been analyzed; the importance also in con- 

 junction with the spleen of its extrinsic functions must now 

 be inquired into. Foster states that "a pancreas taken fresh 

 from the body, even during full digestion, contains but little 

 ready-made ferment, though there is present in it a body which, 

 by some kind of decomposition, gives birth to the ferment. 33 

 . . . To this body, this mother of the ferment, which has 

 not at present been satisfactorily isolated, but which appears to 

 be a complex body, splitting up into the ferment, which, as 

 we have seen, is, at all events, not certainly a proteid body, 

 and into an undeniably proteid body, the name of zymogen 

 has been applied. But it is better to reserve the term zymogen 

 as a generic name for all such bodies as, not being themselves 

 actual ferments, may by internal changes give rise to ferments, 

 for all 'mothers of ferment/ in fact, and to give to the 

 particular mother of the pancreatic proteolytic ferment the 

 name trypsinogen." In other words, and in accord with pre- 

 vailing custom, each zymogen is named from the ferment it 

 produces: the zymogen of trypsin being "trypsinogen"; that 

 of pepsin, "pepsinogen," etc. It is therefore permissible to 

 use the term "amylopsinogen" as the main product of the true 

 lobular acini to differentiate it from trypsinogen, the product 

 of the islands of Langerhans, reserving the term zymogen as 

 a generic term for all pancreatic ferments. As "zymogen" 

 under these conditions, it preserves characteristics attributed 

 to it by Heidenhain; it is soluble in water, in which it is split, 

 after exposure to the air, into trypsin, etc. (Charles). The 

 conversion of trypsinogen into trypsin has been ascribed to 

 oxygen; but if our views are sound and the former is the 

 normal product of the islands, the portion distributed through 

 the pancreatic ducts is intimately combined with the splenic 

 ferment in the ampullae as fast as formed, so that it can never 

 be obtained as trypsinogen per se. Hence, oxygen will split 

 zymogen into trypsin, etc.; but trypsin is not, as stated, oxidized 

 trypsinogen. 



83 These italics are the author's. 



