EUROPEAN rOULBKOOD. 



25 



of a strength twice that dewired in the experiment. After shaking, 

 it is allowed to stand at room temperature. At intervals brood free 

 from the disease is fed a bit of this suspension, using the direct 

 method. Table XIV summarizes the experiments performed : 



Table XIV. — Effect of carbolic acid on Bacillus pluton 



Bate of inoculation. 



Aug. 22, 1914 

 Aug. M, 1914 

 Julys, 1915.. 

 Aug. 21, 1914 

 Sept. 4, 1914. 

 June 29, 1915 

 Julys, 1915.. 

 June 29, 1915 

 Aug. 22, 1914 

 Aug. 14, 1914 

 Aug. 17, 1914 

 Aug. 25, 1914 

 Aug. 22, 1914 

 June 29, 1915 



Strength 



of 

 solution. 



Per cent, 

 i 



1 



Period 

 of sus- 

 pension. 



Days. 



i 

 1 



4 

 8 



18 



15 

 4 



'5 

 '18 

 1 

 4 

 4 

 9 



'5i 



Results of inoculation. 



European foulbrood produced. 



Do! 



Do. 

 No disease produced. 

 European ioulbrood produced. 

 No disease produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



1 Hours. 



The experiments outlined in Table XIV show that Bacillus pluton 

 withstood a one-half per cent solution of carbolic acid for 8 days 

 but not for 18 days; that it withstood 1 per cent for 5 hours but 

 not for 4 days ; and that it was destroyed by 2 and 4 per cent solu- 

 tions, respectively, in less than 6 hours. Probably it is destroyed 

 by these latter strengths in considerably- less time than this. 



It is seen by these preliminary experiments that Bacillus pluton 

 is destroyed easily by carbolic acid as a disinfectant. As a drug, 

 however, less can be expected of it, inasmuch as a strength twice 

 that which the bees will accept in honey (Table XV) requires days 

 to destroy the germ. While the fact does not furnish conclusive 

 proof of the value of carbolic acid as a drug, it indicates what 

 might be expected of it in the treatment of the disease. 



In using the results recorded on the foregoing pages for the 

 purpose of destroying the virus of European foulbrood and con- 

 trolling the disease in practical apiculture, it must be borne in 

 mind, as has been urged in the discussions on the other bee diseases, 

 that due allowance must be made by the beekeeper for variations 

 which always occur. These, however, are relatively slight and can 

 lye met readily. In the destruction of the virus through heating, 

 for example, the temperature can be raised a few degrees above that 

 which is found to be the minimum required, or the time can be 

 extended somewhat. Similarly for the other destructive agencies 

 the effectiveness of the process can be increased. 



