ANTIBIOTIC SUBSTANCES 241 



cavities of the body. Small amounts may bring about the sterilization of 

 local infections without producing general toxic effects, giving only 

 minimal local reactions. When injected into the skin, tyrothricin and 

 gramicidin produce local reaction, the latter to a lesser degree. Oral ad- 

 ministration is ineffective in reducing or destroying organisms which are 

 susceptible m vitro. Local application of these substances has not been 

 attended by toxic reactions even when large amounts were applied 

 (729). Tyrothricin in high concentrations caused cytoplasmic and nu- 

 clear disintegration of the exudative rabbit polymorphonuclear leuko- 

 cytes j in lower concentrations, it brought about altered staining reac- 

 tions. When there was no apparent microscopic injury to the cells, 

 phagocytosis of pneumococci took place. The presence of serum brought 

 about some protection of the cells from the effects of these substances 

 (132). Tyrothricin does not inhibit mitosis or migration of fibroblasts 

 or activities of leukocytes, following direct applications to tissue culture 



(693). 



The filtrate of B. mesentericus was found (956) to have a specific bac- 

 tericidal action on C. difhtheriae in a dilution of i: 1,250. When in- 

 jected parenterally into guinea pigs, it inhibited the toxic effect of the 

 diphtheria organism. The filtrate of the antagonist was found useful in 

 the treatment of diphtheria carriers. 



Particularly favorable results were obtained from the use of grami- 

 cidin in the treatment of chronic mastitis (535). Several cows received 

 treatment with increasing amounts of gramicidin diluted with distilled 

 water. Following the morning milking, the residual milk in the cistern 

 and in the teat was flushed out with 100 to 200 ml. of the gramicidin so- 

 lution, containing 60 to 240 mg. in i ,000 ml. water j 800 to 900 ml. were 

 then injected under pressure into the quarter and allowed to remain 

 until the next milking. Within one hour after the injection, the treated 

 quarter became distended and rectal temperature began to increase, 

 reaching 41° C. at the fifth or sixth hour. The temperature returned 

 to nearly normal in about 3 hours thereafter, the acute swelling having 

 subsided at the next milking. The streptococci disappeared from most 

 of the quarters treated, without an appreciable decrease in milk pro- 

 duction. The fact that streptococci had been eliminated was established 



