336 SPECIFIC' MICRO-ORGANISMS 



important aid in diagnosis, and isolation of the organism from the 

 circulating blood, or from the spleen, and its identification makes 

 the diagnosis certain. Positive cultures are more often obtained 

 from the spleen, but the puncture of this organ by the inexperi- 

 enced is not without danger. Blood cultures should be made dur- 

 ing a febrile period and preferably late in the afternoon. Death 

 occurs in I to 2 per cent of the cases. 



Careful investigations have shown that infection with B. meli- 

 tensis is endemic among the goats of Malta, from which animals 

 is obtained the milk supply of the region. The micro-organisms 

 are excreted in the milk. Monkeys fed such milk acquire the 

 disease, and human epidemics of Malta fever have followed the 

 use of such milk under conditions closely resembling those of 

 critical experimentation. Other methods of transmission have 

 been tested with negative results. 



Immunity follows recovery from the disease, but artificial 

 immunization is not yet a practical success. * 



