WHITE, JULY 29, 1907. 81 
The way by which this difficulty is overcome is reported in the pub- 
lication under consideration. Young pup were used in making the 
medium. ‘These were picked from a comb containing healthy brood, 
crushed, strained through cheesecloth, and then diluted by adding 
water equal to from 20 to 50 times the volume of the crushed brood 
used. This solution was then passed through ordinary filter paper 
and subsequently through a Berkefeld filter. In this way a sterile 
filtrate was obtained. About 2 c. c. of the sterile filtrate was then 
added by means of a sterile pipette to liquefied agar which had been 
cooled to 45° or 50° C. If pure cultures were desired, agar tubes 
thus prepared were inoculated with a small amount of diseased brood 
and plates were poured. If, however, culture growth was desired 
for the inoculation of bees or experimental animals, it was obtained 
from these specially prepared agar tubes by first mclining them 
and then securing the growth by inoculating the surface of the 
inclined agar with a pure culture of Bacillus larve obtained from the 
plates. At no time was this special medium to reach a high temper- 
ature. 
Two colonies were now fed the scales of American foul brood, 
suspended in sirup. American foul brood resulted from these inoc- 
ulations with symptoms the same as are found in an apiary in which 
the disease appeared through the natural means of infection. 
Similar results were reported by Erne (p. 76). These experiments 
were sufficient to prove that American foul brood can be produced 
experimentally by feeding; also, that the scales of the disease 
contained the virus. 
Having demonstrated the fact that American foul brood can be 
produced by feeding and having obtained pure cultures of Bacillus 
larve in suitable form for inoculation purposes, the next step to be 
taken, very naturally, was to inoculate healthy colonies with pure 
cultures of Bacillus larve. This was now done, and as a result of 
such inoculations American foul brood was produced with symptoms 
identical with those produced when the scales were used in feeding. 
The decaying brood in the disease thus produced contained the large 
number of spores that are always found in brood dead of this disease, 
-and from the diseased material pure cultures of Bacillus larve were 
obtained. 
The results obtained from these experiments in which pure cul- 
tures of Bacillus larve were used in making the inoculations justified 
for the first time the statement that American foul brood was caused 
by a specific microorganism. 
It seemed to the author of the circular that probably the species 
which had given different workers considerable difficulty in culti- 
vation, in many cases at least, was nothing other than Bacillus 
13140°—Bull. 98—12-——-6 
