SPERMOTOXIN. 295 



glands, spleen or bone-marrow may be ground up 

 and injected. 



Immunization with solid organs, as liver, kidney 

 or testicle, is easily accomplished, a necessary pre- 

 liminary for injection being a thorough disintegra- 

 tion of the tissue by grinding with sterile sand; 

 the resulting mass when suspended in salt solution 

 passes through the injecting needle readily. 



Cytotoxins, like bacteriolysins and hemolysins, A mboceptof, 

 are complex substances, in that they consist of am- 

 boceptors and complements. The amboceptors toxins. 

 alone are increased during immunization, the com- 

 plement being a normal constituent of the serum 

 of the animal. The phenomena of inactivation 

 and reactivation are observable here as in connec- 

 tion with other cytolytic serums. Anticytotoxins 

 are readily produced by immunization with many 

 cytotoxins; the antiserum usually consists of anti- 

 complement, but in some instances antiambocep- 

 tors have been described. 



Simultaneously, or nearly so, Landsteiner in 

 Vienna and Metchnikoff in Paris reported the 

 production of spermotoxic serums by immuniza- 

 tion with spermatozoa, the natural motility of 

 which rendered the recognition of cell death easy. 

 The technic which Landsteiner first employed was 

 that of the Pfeiffer experiment in that he immun- 

 ized guinea-pigs with the spermatozoa of cattle and 

 observed loss of motility on the part of the cells 

 when they were injected into the peritoneal cavity 

 of the immunized animals. Comparable with 

 many other cytotoxins, spermotoxin kills the ho- 

 mologous cell without causing its solution. The 

 loss of motility is also observed in hanging-drop 

 preparations provided a fresh or a complemented 



