DIPHTHERIA BACILLUS AND MILK 



343 



brought forth numerous colonies of a pure culture of B. diphtheric^. 

 A broth culture was made from one of these colonies, and after 

 forty-eight hours incubation at 37" C. showed the characters of a 

 diphtheria culture, with formation of acid. One quarter of a c.c. 

 was injected subcutaneously into the groin of a guinea-pig, with the 

 result that the animal died in thirty-six hours with a haemorrhagic 

 tumour in the groin, and deep congestion of the viscera. Films 

 and cultures made from the fluid of the tumour showed the diph- 

 theria bacilli in pure culture. Stained by Neisser's method, the 

 bacilli gave a positive result. It was also tested by inoculation 

 into a guinea-pig with -^ cc. of diphtheria antitoxin. The animal 

 remained alive and well. 



Dean and Todd centrifugal ised the milk which they examined, 

 and blood-serum tubes were inoculated from the deposit. In the cul- 

 tures, a few diphtheria-like bacilli were demonstrated, and by further 

 plating, pure cultures were obtained. Morphologically, the bacilli 

 were found to be typical Klebs-Loffler bacilli of medium size. Their 

 virulence was tested as follows : — A twenty-four hours' culture of 

 the bacillus in alkaline broth, was inoculated into five guinea-pigs, 

 thus : — 



dead in 48 hours. 



{\ 



5. G.P. 



250 



2 c.c. of culture . 

 4 c.c. of culture . 



4 c.c. of culture . 

 c.c. diph. antitoxin . 



5 c.c. diph. antitoxin, and 24 

 hours later 2 c.c. of culture . 



5 c.c. diph. antitoxin, and 24 

 hours later 4 c.c. of culture . 



;} 



lived, very slight 

 local reaction. 



The diphtheria antitoxin employed in these experiments con- 

 tained 300 units per cc. (Ehrlich). The toxins of the organisms 

 were also similarly tested, thus : — A pure culture of the bacillus was 

 placed in nine tubes of 10 cc. of alkaline broth in an incubator at 

 36° C. for ten days. The total mixture of the nine tubes was 

 then filtered through a Berkefeld filter. The toxins thus obtained 

 were tested as follows : — 



