THE LEUCOCYTES IN IMMUNITY. 733 



corpore. Thus, he remarks (incidentally, though indirectly, con- 

 firming our view that neutrophiles are the source of fibrinogen 

 granules): "In blood removed from the body the white cells 

 allow plasmane, which causes coagulation of fibrin and the for- 

 mation of the clot, to pass into the liquid. But at the same 

 time these cells abandon a portion of their cytase, which com- 

 municates to the serum its ha^molytic and bactericidal qualities." 

 In the body, however, the need of injury to liberate the cytase, 

 and the stated fact that this- trypsin-laden body (alexin) is 

 strictly intracellular, represent the features of the question 

 that are especially emphasized by Metchnikoff. 



This is accounted for by an important feature of this in- 

 vestigator's views: i.e., he regards the intermediary substance, 

 Bordet's fixative, Ehrlich's amboceptor (our oxidizing sub- 

 stance), as a product of these cells, as shown by the following 

 lines: "The cytases are essentially intracellular soluble fer- 

 ments; the fixatives are, on the contrary, true humoral soluble 

 ferments. But, though circulating in the plasma, the fixatives 

 are unquestionably of cellular origin. This fact was first shown 

 by Pfeiffer and Marx, who found the specific fixative of cholera 

 vibrios in the 'haematopoietic organs/ that is to say, the spleen, 

 the lymphatic ganglia, and the bone-marrow at a period when 

 none were present in the blood." 



We have shown the direct functional relationship between 

 the adrenal system and leucocytosis. That the oxidizing sub- 

 stance, which invades the entire blood-stream in increased quan- 

 tity under the influence of a toxic, should have reached the 

 structures mentioned at an early stage of the morbid process 

 is quite plain. Indeed, the proof adduced by Metchnikoff is 

 easily accounted for without in any way attributing to the leu- 

 cocytes themselves the production of the fixative. We have 

 seen, for instance, that the splenic artery, as a branch of the 

 cceliac axis, is one of the first to receive freshly oxygenized 

 blood; the lymphatic system, which has a serum-containing ca- 

 pacity twice that of the entire blood-system, receives fresh 

 serum from the pulmonary lymphatics, etc., before it even has 

 time to penetrate the blood, etc. Again, none of the leucocytes 

 we have studied afford a single physical or chemical feature 

 tending to suggest that the fixative is a product of these cells. 



