98 Chapter IV 



ferments offers undoubted analogies. I need only recall further the 

 discovery of enterokynase, the soluble ferment of the digestive juice 

 of the dog, which actively stimulates the action of pancreatic ferments, 

 and especially that of trypsin. The recent researches of Delezenne 

 (communicated to the International Congress of Physiology held at 

 Turin in September 1901) support this conclusion in a very im- 

 portant fashion. As already pointed out in Chapter III the entero- 

 kynase of the intestinal juice exerts an action comparable with that 

 of the fixatives of haemolytic serums. Alone, it does not act as a 

 solvent ferment, but when it attaches itself to the fibrin it aids the action 

 of the trypsin in a marked degree. In pancreatic digestion entero- 

 kynase plays the part of the fixatives in the solution of red corpuscles. 



The analogy between the resorption of formed elements and 

 intestinal digestion extends even beyond this. When we inject, into 

 the peritoneal cavity or under the skin of various animals, blood from 

 a different species, the blood serum of the former becomes haemolytic 

 for the red corpuscles of the latter. The solution of these red 

 corpuscles is effected by the alexine of the serum, whose activity is 

 rendered very great owing to the presence of a quantity of specific 

 fixative. This same fixative appears also in the fluids of animals 

 to whom, instead of injecting blood, we simply give it by the mouth. 

 [105] This fact has been established by Metalnikoff'\ 



Another fact in favour of the close relationship between the 

 fixatives and enterokynase consists in the presence of both in the 

 lymphatic (lymphopoietic) organs. The fixatives which aid the solu- 

 tion of red corpuscles are found specially in the mesenteric glands. 

 Enterokynase, as demonstrated by Delezenne, is found not only in the 

 intestinal juice, but also in Peyer's patches, the solitary glands, the 

 mesenteric glands, and the leucocytes of exudations and of the blood. 



Supported by these various facts we are quite justified in regard- 

 ing the haemolysing substance of serum as containing two soluble 

 ferments, of which one, alexine, corresponds to trypsin, the other, 

 the fixative, resembling enterokynase. The alexine, whose nature is 

 gradually disclosing itself with more precision, should bear the name 

 of cytase or cell-ferment. The cytase of the macrophagic organs, or 

 macrocytase, comes under this category. According to the researches 

 of Tarassewitch it also acts more vigorously when there is added to 

 it some of the fixative found in the serum (heated to 56" C.) of 

 prepared animals. 



1 Centralbl.f. Bakteriol u. Parasitenk., l^ Abt., Jena, 1901, Bd. xxix, S. 531. 



