PRESENT BTATU8 OF [NVE8TIGATIOK OF BEE DI8EA8E8, 89 



process of manufacture the bacteria tend to fall to the bottom. The first 

 refining of the wax must, of course, remove the greater quantity, and the \.ist 

 majority of the remainder will settle to the bottom during the process of 

 foundation manufacture. Bui that the simple process of mixing the Infected 

 materia] with the melted wax is qo1 sufficient i<» prevent germination l think Is 

 shown by the results quoted above, where Bimple fragments of Infected wax 

 when placed on agar jelly gave rise to a culture of Bacillus alvi i. 



'This question i hope to toucb on again after I have had an opportunity of 

 supplying healthy bees with foundation made from infected wax. 

 The other question is whether the temperature to which wax is raised dur 



Ing foundation making is sufficiently high to destroy the spores of foul br I. 



In order to decide this question there are several points to be noted. The 

 first is the character of the heat. We know ih.it moisl heat will destroy bac- 

 teria and their spores much more quickly than dry heat, and Mr. Corneil, of 

 Lindsay, has raised this point several times, claiming that the heat to which 

 the bacteria are exposed in melting wax is not moist heal but dry heat, conse 

 quently we must heat to a high temperature and for a long time in order to de 

 stroy the spores. The point is undoubtedly well taken, and can only be settled 

 by direct experiment. In order to determine the temperature .-it which the spores 

 are destroyed in melted wax, I used a method that was firsl described by 

 Ko.ii. Sterilized silk threads were saturated with a beef-tea culture of Bacillus 

 alvei in which there were large numbers of spores. Those threads were then 

 allowed to dry and in the dry state were preserved. These dried threads were 

 introduced into the melted wax and allowed to remain in it tor q definite time 

 at a fixed temperature. At the end of that time the thread was introduced into 

 the melted agar or into beef tea heated to the melting point of wax, and thor- 

 oughly shaken, so as to separate the wax as much as possible from the threads'; 

 then the culture medium was rapidly cooled, and the tubes placed in the ordi- 

 nary cultivating even kept at 98° F. If I obtained a growth of bacilli, I con- 

 cluded that the threads had not been sufficiently heated in the wax; if I did 

 not. I concluded that they had been sufficiently heated. The following are 

 my results : 



At 212* P. ( loo C. i : 



For one-quarter of an hour: Growth. 



For one-half an hour : < Jrowt h. 



For one hour : Growth. 



For one hour and a half : < irowth. 



For two hours : Growth. 



For two hours and a half: No growth. 

 At 194° F. i '.mi C.) : 



For one half hour : < irowt h. 



For one hour : Growth. 



For two hours : Growth. 



For three hours : No growt h. 



For four hours : No ( rrowi h. 

 on the other hand, ;i temperature of 122° F. (50 <'. I did no1 destroy the 

 spores in twenty-four hours. 



I have repeated these ex ] >eri mem s several times with the same results, so 

 that I would conclude that to destroy the foul brood in wax it is necessary to 

 heal to a temperature of at leasl 194 F. for at leasl three hours. Now the 

 question arises, does this take place during the process of manufacture of comb 

 foundation? in order to get as much data as possible on the subject I wrote 

 to Mr. l.arrahee. of Michigan Agricultural College, as he had kindly offered me 



