610 THE INTERNAL SECRETIONS AND IMMUNITY. 



caused by the thistle is precisely that caused by the medusa, and 

 is traceable to the same agency, formic acid: the irritating prin- 

 ciple of the caterpillar, the ant, and other insects. Calmette 1 

 found that cobra-venom caused, in the conjunctiva, an inflam- 

 matory process precisely similar to that brought on by abrin 

 and jequirity. ' We are also familiar with the beautiful experi- 

 ments of Ehrlich with abrin and ricin: two albuminoid vege- 

 table poisons which correspond with bacterial poisons even to 

 their being able to confer immunity. Just as there are harm- 

 less cells in the animal structure, so are there harmless cells 

 in vegetable structure. In the ascending steps of morbidity, 

 in which these benign organisms may take part under the 

 influence of various reactions, we witness, howev.er, not only 

 a biochemical parallelism in all phenomena engendered, but 

 also, as rightly contended by Charrin, 2 a common symptoma- 

 tology. Thus, in their physical interchanges, morbid effects, 

 and semeiology, all cellular structures, can be united in a com- 

 mon class. 



THE ADRENAL SYSTEM IN ITS RELATIONS TO PHAGOCYTOSIS 

 AND LEUCOCYTOSIS. 



Metchnikoff terms "phagocyte" any cell deprived of a 

 cellular membrane and capable of incorporating bacteria and 

 other substances, and of disintegrating them. In the blood, 

 certain leucocytes, particularly the mobile or wandering neutro- 

 philic or polymorphonuclear forms (the "microphages"), the 

 fixed endothelial and connective-tissue cells, those of the 

 splenic pulp, and the large lymphocytes of the blood ("macro- 

 phages"), are endowed with this property. Precisely as do the 

 familiar amoeba, so do these phagocytes ingest bacteria and 

 assimilate them. An animal is immune, according to Metch- 

 nikoff, as long as its phagocytes freely take up and destroy 

 pathogenic organisms. In proportion, on the other hand, as 

 the functions of the phagocytes are impeded, so is the animal 

 susceptible to disease. That living and dead bacteria are thus 

 disposed of seems to have been satisfactorily shown, while 

 chemotaxis fairly accounts for the affinity which phagocytes 



1 Calmette: Annales de 1'Institut Pasteur, vol., 1892. 



2 Charrin: "Poison des Tissus," quoted by No6, loc. cit. 



