538 CYTOTOXINS 



It is not rarely observed that in large tumors and similar lesions 

 certain groups of cells may undergo digestion, but in these the lysis is 

 commonly ascribed to the action of ferments liberated upon the death 

 of cells. 



Isocytotoxins have been produced experimentally, as, for example, 

 by Ehrlich, who produced isohemolysins by injecting goats with goat 

 blood, and by Metchnikoff, who prepared isospermatoxic serums. 



Anticytotoxic serums have likewise been prepared by careful im- 

 munization with cytotoxic serums. 



Varieties of Cytotoxins. As previously stated, attempts have been 

 made to prepare cytotoxic serums for practically all the organs and tis- 

 sues. Since none of these has been found to be absolutely specific, 

 and hence since they possess little or no practical value, they will receive 

 but brief consideration here. 



1. Spermatotoxin. This serum was prepared simultaneously by 

 Metchnikoff 1 and Landsteiner in 1899, and was one of the earliest 

 cytotoxins to be studied. It is a hemolytic serum, and causes sperma- 

 tozoa to lose their motility. It would seem to affect also the vitality 

 of the spermatozoa in vivo, inasmuch as De Lester, by the injection of 

 this serum, rendered male mice sterile for from sixteen to twenty days. 



2. Epilheliotoxin. A cytotoxic serum for the ciliated epithelium of 

 the trachea was prepared by von Dungern. 2 The cells became dis- 

 integrated in the peritoneal cavity of the immunized animal, but not in 

 that of the normal animal. This serum also proved to be hemolytic. 



Similar serums have been prepared with cancer cells, in the hope 

 of establishing a specific serum therapy, but all efforts have thus far 

 proved futile. 



3. Leukotoxins. This serum was first prepared by Metchnikoff 3 

 and Besredka 4 by injecting the spleen of rats into guinea-pigs. The 

 serums have also been prepared by effecting immunization with exudates 

 rich in leukocytes or with the emulsion of lymphoid organs (Flexner 

 and Ricketts). They are usually hemolytic, and also attack endothelial 

 cells. Their action may be observed in vitro when the leukocytes lose 

 their ameboid motility and the protoplasm swells, clears, and may dis- 

 integrate, leaving the nucleus. 



4. Nephrotoxin. This serum is best adapted for experimental studies 



1 Ann. de 1'Inst. Pasteur, 1900, xiv, 369. 



2 Munch, med. Wochenschr., 1899, xlvi, 1228. 



3 Ann. de 1'Inst. Pasteur, 1899, xiii, 737. 



4 Ann. de 1'Inst. Pasteur, 1900, xiv, 402. 



