DESTBUCTION OF GERMS OF BEE DISEASES BY HEATING. 5 



Table II. — A summary of the experiments made to determine approximately the minimum 

 amount of heating necessary to render sacbrood material noninfectious. 



From Table II it will be observed that when larvae dead of sacbrood 

 were heated 10 minutes at atemperature of 57° C. (134.6° F.) or less 

 and then fed to a healthy colony, sacbrood was produced ; if, on the 

 other hand, the dead larvae used in making the feeding were heated 

 to 58° C. (136.4° F.) or higher, the disease was not produced. The 

 conclusion to be drawn from these experiments is that the minimum 

 temperature, when maintained for 10 minutes, at which the infecting* 

 agent causing sacbrood is destroyed Hes somewhere between 55° C. 

 (131° F.) and 60° C. (140° F.), being near 58° C. (136.4° F.). 



DISEASES OF ADULT BEES. 



Very Httle is known about the diseases of adult bees. Many names 

 have been used for the purpose of designating them, but the number 

 of siich diseases is probably small. There is only one adult disease 

 that can be diagnosed at present by laboratory methods. This one is 

 the Nosema disease. 



NOSEMA DISEASE. 



Fifty-seven years ago Dr. D6nho£E made a more or less brief study 

 of a disease of adult bees in Germany. He observed that the stomach 

 was the organ that was primarily affected. By feeding to healthy 

 colonies in sirup the crushed stomachs from affected bees Donhoff 

 demonstrated that the disease could be transmitted to healthy colo- 

 nies. It was therefore infectious. 



The work by Donhoff hati been practically forgotten, apparently, 

 when Zander,^ of Erlangen, Germany, five years ago observed the 



1 Zander, E., Aug., 1909. Tleriscbe Farasiten als Krankbeitserreger bei der Biene. Miincliener Bienen- 

 zeitung. - 



