74 HISTORICAL NOTES ON BEE DISEASES. 



Bahr, 1906. 



Another publication by Bahr ' appeared in 1906, in which he gives 

 the resuhs obtained from his further investigations. He reports that 

 more than 200 cases of foul brood had been examined. The following 

 points are noted in Bahr's paper: 



1 . One can not be sure with what disease he was working. 



2. He does not always find Bacillus alvei in foul brood. 



3. With cultures of Bacillus alvei he was not able to produce foul 

 brood either by spraying the larvae or by feeding cultures of the 

 bacillus. He failed also to produce the disease by using the contents 

 of the dead larvae for spraying or as food in sugar sirup. 



4. He suggests that the reason for these negative results may be 

 either that Bacillus alvei is not the cause of foul brood or that the 

 proper time or manner in which such infection can be produced 

 experimentally had not been discovered. 



5. He did not find any other bacillus as a possible cause of the 

 disorder. Bacillus alvei was not found in the eggs or in the sexual 

 organs of the queen, as had been reported by Cheshire (p. 21), Har- 

 rison (p. 49), and others. 



6. He suggests that possibly the cause of the disease is an ultra- 

 visible virus and that possibly the disease is transmitted through the 

 queen. 



It appears likely that Bahr was working with European foul brood, 

 but this is not at present positively known. If he studied American 

 foul brood, he must have overlooked the fact that there are numerous 

 spores {BaciUus larvse) present in the decaying remains of the larvae 

 which do not grow on the artificial media commonly used. In sup- 

 port of his theory that the disease is transmitted by the queen he 

 says that he has introduced a queen from a diseased colony into a 

 healthy one and produced foul brood as soon as the queen could lay 

 the eggs, and that he has mtroduced queens from healthy colonies 

 into apparently doomed ones with the result that the diseased colonies 

 quickly recovered. 



These experiments should be repeated for a confirmation of the 

 results. If, as is probable, Bahr worked with European foul brood, 

 there were probably other factors present which were not accounted 

 for. His failure to find BaciUus alvei in all the samples examined 

 is interesting, and his failure to produce foul brood with cultures 

 of Bacillus alvei repeats the experience of some others. 



1 Bahr, L., 190G. Om Aarsagen til Bipesten og dennes Beksempelse. Foredrag holdt ved DBF's Dis- 

 kussionsm0de d. 2 Septbr. 1906 1 Esbjerg. SjErtryk af Tidsskrift for Biavl. Nr. 17. 



