THE CAUSE OF EUROPEAN FOUL BROOD. 13 



for the " gynthert-ioviws " which he observed in his ciiUures. Maassen 

 mentions some difficulty experienced at times in obtaining Strepto- 

 eoeeus ap^'s from brood which on microscopic examination seemed to 

 contain this bacterium. To explain this difficulty, lie advanced the 

 supposition that the Streptococcus was probably killed by acid pro- 

 duced by itself. The difficulty probably could be as well explained 

 by supposing that Maassen failed to differentiate this parasite from 

 the bacterium which he cultivated and described as Streptococcus apis. 



IS THERE MORE THAN OXE DISEASE IN THE CONDITION KNOWN AS 

 EUROPEAN rOUL BROOD? 



The question now arises whether or not there is more than one 

 disease in the condition now known as European fend brood. In 

 Switzerland and in Germany there has been a tendency to diagnose 

 the diseased brood in which Bacillus alvei is found as the foul brood 

 of Cheshire and Cheyne and the diseased brood in which Strepto- 

 coccus apis is found as " sour brood." From the facts at hand the 

 writer is strongly inclined to believe that these two conditions are 

 only the one disease, known in America as European foul brood. 

 Enough evidence has not yet been obtained, however, to speak with 

 complete positiveness on. this point. 



As secondary invaders some of the species of bacteria mentioned 

 in this paper may and probably do exert an influence on the course 

 of the disease in the larva and in the colony. To what extent these 

 bacteria modify the disease is yet to be determined. Shoidd it be 

 found that Barilhis alvei actually causes an infectious brood disease,, 

 then such a disease should be called European foul brood, and the 

 disease caused by Bacillus pluton would have to be differentiated 

 from it. 



Further details Avill not be given in this preliminary announce- 

 ment but will be included in more technical papers which are being 

 prepared. 



SUMMARY AND CONCLUSIONS. 



The steps taken in the writer's endeavor to find the cause of Euro- 

 pean foul brood may be briefly summarized as folloAvs: 



(1) Bacillus alvei, which has been so generally spoken of as the 

 cause of foul brood, M-as isolated from diseased brood, and pure cul- 

 tures of the organism in both the vegetative and spore forms were 

 repeatedly fed to colonies of healthy bees Avitli the result that foul 

 brood was not produced in any instance. This fact cast a suspicion 

 that Bacillus alrei was probably not the cause of a disease. 



(2) By a study of many larvae in samples of European foul brood 

 it was frequently found that there were larvae apparenth^ dead of the 

 disease that contained Bacillus alvei only in small numbers or not at 



