PRESENT STATUS OF INVESTIGATION OF BEE DISEASHES. 39 
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 vast 
majority of the remainder will settle to the bottom during the process of 
foundation manufacture. But that the simple process of mixing the infected 
material with the melted wax is not sufficient to prevent germination I think is 
shown by the results quoted above, where simple fragments of infected wax 
when placed on agar jelly gave rise to a culture of Bacillus alvei. 
This question I hope to touch 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 brood. 
In order to decide this question there are several points to be noted. The 
first is the character of the heat. We know that moist 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 heat 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 at which the spores 
are destroyed in melted wax, I used a method that was first described by 
Koch. Sterilized silk threads were saturated with a beef-tea culture of Bacillus 
alvei in which there were large numbers of spores. These 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 for a 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 oven kept at 98° EF. 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: 
Atel 2 eh (OOLSCS)) : 
For one-quarter of an hour: Growth. 
For one-half an hour: Growth. 
For one hour: Growth. 
For one hour and a half: Growth. 
For two hours: Growth. 
For two hours and a half: No growth. 
At 194° BY. (905)C.): 
For one-half hour: Growth. 
For one hour: Growth. 
For two hours: Growth. 
For three hours: No growth. 
For four hours: No Growth. 
On the other hand, a temperature of 122° F. (50° ©.) did not destroy the 
spores in twenty-four hours. 
I have repeated these experiments several times with the same results, so 
that I would conclude that to destroy the foul brood in wax it is necessary to 
heat to a temperature of at least 194° F. for at least 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. Larrabee, of Michigan Agricultural College, as he had kindly offered me 
