THE LEUCOCYTES IN ORGANIC FUNCTIONS. 693 



canal from the follicles, the proportion of blood-plasma in them 

 must be limited when, laden with proteids, they enter the ven- 

 ules of the villi to find their way to the portal vein. Even in 

 this vessel they must again find a dearth of oxidizing substance, 

 for we have seen that this channel is essentially venous. We 

 must not lose sight of the fact, however, that potent additions 

 to its contents are obtainable here: the spleno-pancreatic in- 

 ternal secretion, i.e., trypsin, to which the plasma of arterial 

 blood and dextrose may be superadded when the precincts of 

 the hepatic artery, i.e., the hepatic lobules, are reached. 



If these cells do take up proteids and other bodies utilized 

 in nutrition or in the building up of various organic structures, 

 their own canaliculi, i.e., those of the cell-substance, must serve 

 as the eliminatory channels. In other words, proteids ingulfed 

 by the leucocyte must be submitted to a process of digestion 

 in the nucleus and its vacuole, and the products be passed out 

 as granules. This elevates leucocytes to the rank of glandular 

 organs, but we must not overlook the fact that glands in gen- 

 eral supply their secretion in the form of granules. Eeferring 

 to the parotid, for instance, Professor Foster speaks of the 

 secretion as "generally in the form of granules" and of the 

 "granules" which in the submaxillary gland "may obscure the 

 nuclei/' The granules of the pancreas, of the intestinal epi- 

 thelial cells, etc., are also familiar examples. Indeed, all these 

 granules only differ from those of leucocytes in being less com- 

 plicated molecularly and smaller.- They seem to us fully to 

 represent a true, cellular secretion. 



What is the nature of the neutrophile's secretion, i.e., the 

 composition of its granules? Milroy and Malcolm 24 state that 

 the finely-granular amphophile (or neutrophiles) granules "are 

 usually taken to be proteid in nature," and refer to the fact 

 that Sherrington had suggested that they might be "of nucleo- 

 proteid nature": a view which their own researches confirm. 

 Under the action of alcohol kept at boiling-point, neither fine 

 nor coarse oxyphile granules were dissolved; ether also at boil- 

 ing-point gave similar results. These agents being then used 

 successively, the granules remained practically unaltered: a 



24 Milroy and Malcolm: Journal of Physiology, vol. xxv, 1899. 



