CHAPTER VII 



FURTHER DEVELOPMENT OF OUR KNOWLEDGE CON- 

 CERNING COMPLEMENT OR ALEXIN. COMPLE- 

 MENT FIXATION 



IT will be remembered that Buchner in his first studies upon the 

 "alexin" compared its action to that of an enzyme or ferment, and 

 suggested that the source of this substance might possibly be found 

 in the white blood cells. This thought was very obviously suggested 

 by the observation that bacteria were destroyed within the white 

 blood cells, after phagocytosis, by a process analogous in many ways 

 to that by which they were destroyed by the serum constituents. 

 Hankin, 1 in an elaborate study dealing with the problem, maintained 

 the leukocytic origin of alexin on the basis of the observation that 

 increased bactericidal properties closely followed upon the heels of 

 periods of leukocytosis. He assigned the particular property of 

 alexin production to the eosinophile cells, proposing for them the 

 designation "alexocytes." Further study, however, has not justified 

 such an association with the eosinophiles, and Hankin' s opinion has 

 not been experimentally upheld. 



After Hankin the problem occupied the attention of a number 

 of other investigators, and many of them succeeded in showing that 

 there was, indeed, an increased bactericidal power in exudates rich 

 in leukocytes, and further that bactericidal substances could be 

 directly extracted from leukocytic emulsions. We refer particularly 

 to the early work of Denys and Havet, 2 of Hahn, 3 of Van de Velde, 4 

 and others, studies which will be described in our chapter on 

 phagocytosis. This work was done before the complex nature of the 

 bactericidal constituents of serum had been demonstrated and before 

 the work of Schattenfroh and others had shown that the bactericidal 

 substances extracted from leukocytes were of a nature quite distinct 

 from the active elements of the serum, and were independent of the 

 participation of alexin. Although these earlier investigations cannot 

 properly be regarded, therefore, as proving the leukocytic origin o 



1 Hankin. Centralbl f. Bakt., Vol. 12, 1892. 



2 Denys and Havet. La Cellule, Vol. 10, 1894. 



3 Hahn. Archiv f. Hyg., Vol. 25, 1895. 



* Van de Velde. La Cellule, Vol. 10, 1894. 



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