48 histokical notes on bee diseases. 



Haeeison, Decembee, 1900. 



The next paper to be considered is one by Harrison.* In comment- 

 ing upon the work of Cheshire and Cheyne, he asserts that these men 

 established the causal relation of Bacillus alvei to foul brood by 

 successfully applying Koch's rules in their work. He rehearsed in 

 his paper the spraying experiment which Cheshire was supposed to 

 have done and stated that since that time Bacillus alvei has generally 

 been regarded as the cause of the disease. 



In the beginning of his work, then, Harrison, hke Mackenzie, 

 accepted the work of Cheshire and Cheyne as conclusive that Bacillus 

 alvei is the cause of foul brood. It is very unfortunate that these 

 two men should have made this mistake, as their papers have had 

 the effect of strengthening two erroneous ideas: First, that the two 

 maladies which together were known as foul brood were one disease; 

 and second, that Bacillus alvei is the cause of the disorder. 



Harrison was aware of the fact that some bee keepers beheved 

 that there was more than one disease included under the name foul 

 brood, since, in commenting on the work of Dickel and Klamann, he 

 states that Dickel writes of one form of the disease which affects 

 the unsealed brood, and of another form which affects the sealed, 

 and even a third form, a mixed form which seems to be still more 

 mahgnant. He states furthermore that Klamann suspected two 

 kinds of disease. 



Harrison entertained the following ideas concerning foul brood. 

 The disease affects chiefly the larvae, and when they are attacked 

 they no longer Ue curled up in the cell but are extended in it or move 

 about unnaturally. The adult bees by a sort of inertness which seizes 

 them may at this time show symptoms of the disease. The affected 

 larvae become flabby and die, and as a result of the decomposition 

 which sets in, the decaying mass takes on a yeUowish color. The 

 yeUow turns to a brown and when touched by a pin at this time or 

 later, a portion of the mass may be pulled out in a long, ropy, tena- 

 cious string. This ropy mass dries down gradually to a brown scale 

 which adheres to the wall of the cell. The bees as a rule are not 

 active in removing larvae dead of this disease from the cells, but, on 

 the contrary, they are quite inactive, without deske to fly, but they 

 may be seen fanning at the entrance of their hive. At this time a 

 foul odor may be detected coming from the hive. The phase of the 

 disease which some authors discuss as being a different form, Har- 

 rison states, is the same disease but that the larvae die after being 

 capped over instead of before. The capping of the ceUs containing 

 such larvae becomes indented or sunken and finally perforated. By 



' Harrison, F. C, B. S. A., December, 1900. Foul brood of bees. Bulletin 112, Agricultural Collegeand 

 Experimental Farm. Pp. 32. Toronto. Portions of this bulletin are quoted in Bulletin No. 70, Bureau 

 of Entomology, U. S. Department of Agriculture, pp. 23-26. 



