SB 
818 
C578 
ENT 
| No. 94. Issued July 29, 1907. 
mited States Department of Agriculture, 
BUREAU OF ENTOMOLOGY. 
L. O. HOWARD, Entomologist and Chief of Bureau. 
THE CAUSE OF AMERICAN FOUL BROOD.) 
By G. E-WHitn; Phy Ds, 
Meapert in Bacteriology. 
For several reasons much confusion exists as to the present status of 
our knowledge of bee diseases. It is hoped that this circular will give 
information which will to some extent clear up the subject of American 
foul brood from a bacteriological point of view. The symptoms of this 
disease are given in Circular No. 79 of the Bureau of Entomology, 
entitled *“The Brood Diseases of Bees.’? American foul brood is the 
prevalent disease in America, and, judging from reports received from 
Europe and from descriptions in European bee journals and books, it is 
the prevalent one there. There is another diseased condition, which 
Cheyne examined, and to which we now refer as European foul brood. 
When the author began his work on bee diseases in the summer of 
1902 he observed, in combs containing American foul brood, in the 
dried remains of the dead larvee, known as the scales, a very large num- 
ber of spores which failed to grow when inoculated into the media ordi- 
narily used in the laboratory. It was clear, then, that these spores are not 
Bacillus alvei and that this disease is not the “‘ foul brood’’ ‘of Cheshire 
and Cheyne. The following year the study was continued and a medium 
was devised in which the spores found in this disease will germinate. 
This medium consists of an agar made by following the directions ordi- 
narily used in the laboratory, with the exception that bee larve are sub- 
stituted for meat. By the use of this medium were obtained pure cul- 
tures of the microorganism which is found so abundantly, in the form 
of spores, in the dried scales of American foul brood. 
In reporting these findings the author referred to this organism as 
“ Bacillus X.’’ Further study was subsequently made, and the species 
was given the permanent name Bacillus larve. The description of 
this species may be found in Technical Series No. 14 of this Bureau. 
In his publications the author has made no claim that Bacillus larve 
is the cause of American foul brood, but has made the statement that 
it is found to be present in all the samples of this disease which have 
1The author wishes to acknowledge the assistance of Dr. EK. F. Phillips, in 
Charge of Apiculture, under whose direction this work has been done. These 
results have been reached since the author has been connected with the apicul- 
tural investigations of the Bureau of Entomology. 
