CYTOTOXINS 221 



3 c.c. respectively are given intravenously on successive days, 

 and after an interval of 5-7 days the rabbit's serum should be 

 strongly hsemolytic. Very active hsemolytic sera may be pur- 

 chased. The serum may be collected aseptically, inactivated by 

 heating to 56 C. for half an hour, and preserved in sealed 

 ampoules. 



CYTOTOXINS. Anti-sera, analogous to the hsemolysins or 

 hsemotoxins, may be prepared which have a destructive action 

 upon cellular elements ; these are termed " cytotoxins." If a 

 rabbit be injected with bull's semen, its serum (" spermotoxin ") 

 acquires the property of immobilising the spermatozoa of the bull. 

 The reaction is specific, but spermatolysis does not seem to occur. 

 Similarly, by injecting ciliated epithelium into the peritoneum of 

 a guinea-pig an anti-epithelial serum, or " trichotoxin," is deve- 

 loped. With liver, kidney, and nerve cells anti -bodies having a 

 destructive action upon these cells are developed as a result of 

 their injection. Nephrotoxin, the serum of an animal inoculated 

 with an emulsion of kidney, when injected into a second untreated 

 animal, produces albuminuria and uraemia with disintegration of 

 the epithelium of the convoluted tubules ; hepato toxin, the serum 

 of an animal treated with emulsions of liver, produces fatty and 

 inflammatory changes in the liver resembling phosphorus poison- 

 ing ; neurotoxin, the serum of an animal treated with emul- 

 sions of nerve tissues, produces paresis, paralysis, depression, 

 convulsions, etc. ; a leucotoxic serum obtained by injecting 

 leucocytes agglutinates and dissolves the leucocytes, and so on. 

 The formation and mode of action of these cytotoxins resemble 

 those of the hsemolysins. It was hoped that the study and pre- 

 paration of cytotoxins would open up possibilities in the way of 

 treating such diseases as carcinoma and sarcoma, but so far this 

 hope has not been realised. 



AGGLUTINATION. If an animal be injected with sub- 

 lethal doses of living or dead bacterial culture, e.g. typhoid 

 or cholera, its serum soon acquires the property of agglu- 

 tinating, that is, of aggregating into masses or clumps, 

 typhoid bacilli or cholera vibrios respectively when added 

 to a broth culture or uniform suspension of these organ- 

 isms. The reaction may be observed microscopically in a 



