94 HISTOEICAL NOTES ON BEE DISEASES. 



During the following decade there continued to be different opinions 

 entertained as to the classification of the infectious brood diseases. 



Many bee keepers were convinced from their experience with the 

 diseases of the brood that there existed two distinct infectious dis- 

 orders (p. 60). By a more careful study of these diseases it has been 

 shown positively that the brood is attacked by more than one infec- 

 tious disease. 



These diseases as understood by the writers of this bulletin are 

 briefly discussed on pages 11 and 12. 



The classification of the adult bee diseases is yet very unsatisfac- 

 tory. 



THE CAUSES OF BEE DISEASES. 



As exciting causes of bee diseases different workers have from time 

 to time suggested different agents. 



Schirach (1771) (p. 13) suggested two causes for foul brood — improper 

 food as one, and a fault of the queen as a second. 



Leuckart had at first inclined to the view that the infectious foul 

 brood was due to a fungus, but from his observations made in 1860 

 (p. 14) he arrived at the conclusion that tliis was not true. 



Molitor-Miihlfeld (1868) (p. 15) attributed the cause to a parasitic 

 ichneumon fly, Ichneumon apiu?n mellificarium. 



Preuss (1868) (p. 15) and Schonfeld (1873-74) (p. 16) were inclined 

 to believe that an infectious form of foul brood was due to a fungus, to 

 which the former gave the name Cryptococcus alvearis. 



Cheshire (1884) (p. 21) and Cheyne (1885) (p. 34) were inclined 

 to believe that foul brood was due to a bacillus. Bacillus alvei. 



The same disease which Cheshire and Cheyne studied came to the 

 attention of William R. Howard in 1900 (p. 46), and he declared that 

 the cause of it was a bacillus, to which he gave the name Bacillus 

 milii. * 



Recent work (p. 81) has proven that American foul brood has as 

 an exciting cause a specific bacillus, to which the name Bacillus larvse 

 has been given. 



The writers of this bulletin believe that the causes for the other 

 bee diseases have not as yet been satisfactorily demonstrated. 



