46 HISTORICAL NOTES ON BEE DISEASES. 



milii and declared it to be the specific germ of "black brood"; the 

 other he named Bacillus thoracis and thought probably that it modi- 

 fied the disease in some way. He said so little about either of these 

 species that neither of them can be identified from his writings. In 

 his examination of five specimens received from West, he reports 

 Bacillus milii in all of them, Bacillus thorac 's in two, and Aspergillus 

 pollini in two. 



In his experimental investigations Howard used two nuclei which 

 were free from disease, and fed each of them a culture of "Bacillus 

 milii" in one-half pint of sirup on November 7, and repeated similar 

 feedmgs on November 10. The feeders were removed from each 

 hive on November 12. When the bees were examined on November 

 26, no brood at all was found in one of the nuclei. In the other 

 nucleus was found no eggs, but larvae six or seven days old and con- 

 siderable capped brood. Near the outer part of the brood-nest 

 apparently some capped cells were found from which were taken 

 nearly matured pupa?. Other pupse, nearly white, with a dark 

 spot on the abdomen, were removed, together with others wMch 

 were dark or black all over. "Bacillus milii" was reported to have 

 been found microscopically in nearly every pupa examined. Howard 

 states that no uncapped larvae seemed from gross appearance to 

 be affected, but in the bodies of several of them Bacillus milii was 

 found. The two nuclei were again examined on December 14. As 

 before, there was nothing ^vi'ong apparently with one nucleus. In the 

 other nucleus there were about 30 capped cells which contamed 

 dead pupse that were nearly black, Mcroscopic examination 

 caused him to report the presence of Bacillus milii in all of these 

 pupse. 



It will be observed that the results which Howard obtained from 

 the inoculation of the two nuclei with cultures of "Bacillus milii" 

 neither proved nor disproved the causal relation of "Bacillus milii" 

 to "black brood." As evidence to support his declaration that 

 Bacillus milii is the specific cause of black brood, modified probably 

 at times by Bacillus thoracis, he offers the data that Bacillus milii 

 was found in all of the few samples which he examined, and that 

 in a few instances Bacillus thoracis was also present. 



In pointing out the differences between "foul brood," "pickled 

 brood," and "black brood," the following tliree assertions are made 

 by Howard; not one of them, however, has yet been demonstrated 

 to be true. 



Foul brood, pickled brood, and black brood. Foul brood, due to Bacillus alvei — 

 a specific bacterium. 



Pickled brood, due to Aspergillus pollinis—?^ specific fungus. 



Black brood, due to Bacillus milii, modified, perhaps, by Bacillus thoracis, specific 

 bacteria. 



