114 MILK HYGIENE 



milk directly from this sick person; the other 12 had 

 received milk from the same dairy but it had been deliv- 

 ered by another man. In this outbreak there were 24 

 deaths. L.P.] A great many other reported cases 

 might be quoted. 



As yet the diphtheria bacillus has rarely been iso- 

 lated from market milk but, notwithstanding this, there 

 can be no doubt of its occurrence in milk and that it may 

 thus cause epidemics like those mentioned above. The 

 bacillus must come directly or indirectly from the oral 

 cavity of people who are or have been recently attacked 

 by diphtheria. Just as the typhoid bacillus is main- 

 tained in many cases in the urine of convalescents, it is 

 also very common for diphtheria bacilli to retain life for 

 months, even for a whole year, in the oral cavity and 

 on the mucous membrane of the nose in persons who 

 have been affected, but who have entirely recovered from 

 the disease. It is on this account that it was possible in 

 only a few epidemics of milk-borne diphtheria to dis- 

 cover the original source of infection and it is difficult, 

 not to say impossible, to wholly guard against the occa- 

 sional infection of milk by diphtheria bacilli. Fortun- 

 ately, these bacilli are frequently of low virulence. 



The opinion, that was held formerly by some, that 

 diphtheria in man could come from a disease of milch 

 cows, is entirely erroneous. 



It has been stated that diphtheria bacilli grow readily 

 in raw milk and that they thrive less well in boiled milk 

 (Schottelius) ; but from the experiments made by Meyer, 

 it appears that diphtheria bacilli act as other bacilli ; that 

 is, that they are checked by the germicidal power of 

 fresh raw milk and grow best in boiled milk. 



Diphtheria bacilli withstand acidity and may there- 

 fore be present in the different dairy products, but the 

 infectivity of the latter has not yet been determined. 



