PRINCIPLES OF VETERINARY SURGERY 121 



human, the case is far different. Like the staphylococcus it 

 has a variable virulency. The cultures are most virulent to 

 the species of animals from which they are taken. Often a 

 culture from one species will prove rather innocuous to an- 

 other. Marmorek secured the highest virulence by passing 

 the coccus through rabbits and then cultivating it in 

 media composed of human blood serum and bouillon. Hoist 

 reports a virulent artificial culture that was kept, without 

 special precautions, for eight years. They possess a remark- 

 able tolerance to desiccation. 



Toxic Products. — It has not been shown that the strep- 

 tococcus pyogenes elaborates any considerable amount of 

 free toxin. Cultures sterilized by heat are, however, cap- 

 able of causing a fatal intoxication. . The toxic products of 

 the streptococcus pyogenes is said to exert a specific cura- 

 tive action on certain malignant tumors, notably on sar- 

 comatous growths. It has been observed that such tumors 

 occasionally sloughed out and cicatrized when accidentally 

 infected with streptococci ; this circumstance has led to the 

 experimental inoculation of tumors with sterilized cultures. 

 Numerous reports of favorable results from prominent in- 

 vestigators would indicate that the expedient is not without 

 merit. 



Antitoxin. — The value of the antitoxins used against 

 streptococcic infections is a matter for future determination. 

 While flattering results are repoi'ted here and there, the 

 antistreptococcic serums have not come into general use in 

 either human or veterinary medicine. 



The antitoxin is prepared by securing a high degree of 

 immunity in a horse, through the repeated injection of viru- 

 lent cultures of the micro-orgatiism. The process is not un- 

 like the preparation of antitetanic serum. 



6. BACILLUS COLI COMMUNIS.— Next to the sta- 

 phylococci and the streptococcus pyogenes, the bacillus coli 



