BURRI, JANUARY, 1906. 71 
other types of rods found in sour brood cells are independent organisms, each with its 
own cycle of development. If various pathogenic bacteria are met with in a disease, 
medical men speak of the condition as a mixed infection. It seems that generally in 
sour brood we have to deal with such a mixed infection. As already pointed out, I 
have, occasionally in the microscopic examination, but particularly in the cultural 
tests of the comb material sent in, encountered the mixed infection of sour brood and 
foul brood so regularly, that I scarcely expect to meet with a case of pure sour brood. 
By this I mean a comb with sour brood cells in which at the same time foul brood 
germs are not to be found. ‘This presumption, however, proved not to be true, for the 
specimen from Kaltbrunn must be considered as a case of ‘“‘pure’’ sour brood. The 
first specimen from Murten which similarly gave the impression at first of being 
‘‘yure,’’ had to be considered subsequently to be foul brood, for the second specimen 
from the same source showed unquestionably the presence of Bacillus alvet. 
The samples containing dead brood, which Burri studied from May, 
1903, to September, 1905, were grouped under four headings, viz, 
‘‘sour brood,” ‘‘stinking foul brood,’ ‘‘nonstinking foul brood,” and 
‘dead brood free from bacteria.” 
In summing up Burri’s work on “‘sour brood”’ the following inter- 
esting facts might be mentioned: 
1. The origin of the term “sour brood”’ is not definite. 
2. Burri considered three gross characters to be of especial value in 
the diagnosis of ‘“‘sour brood’’—a sour odor, a lack of ropiness of the 
decaying larve, and a dirty yellow color of the brood recently affected. 
3. In “‘sour brood”’ were found a large number of short rods which 
resemble, on microscopic examination, Bacteriwm giinthert found in 
sour milk, and with these he found other rods of medium and large size. 
4. When cultures were made from the larve dead of ‘‘sour brood,” 
the giinthert-forms did not grow as a rule, but in their stead cultures 
of Bacillus alver appeared sometimes in pure culture. 
5. The cultivation of the giinthert-forms is reported as having been 
successful. | 
6. Burri believed that ‘“‘sour brood” and the “‘stinking foul brood”’ 
are usually found together. This was suggested to him by the 
frequent presence of Bacillus alvei and the giintheri-forms in the same 
diseased colony. ‘‘Sour brood’’ was reported to have been found 
alone in one instance. 
7. He grouped the samples of comb which contained dead brood 
into four conditions, viz, ‘“‘sour brood,” “‘stinking foul brood,”’ ‘‘non- 
stinking foul brood,” and ‘“‘dead brood free from bacteria.”’ 
_ 8. The true menace to bees he believed to be due to a bacillus 
which is difficult to cultivate. 
We are not inclined to agree with all the views expressed by Burri 
in his work on “‘sour brood.’”’ The condition referred to as “sour 
brood” and ‘‘stinking foul brood” are probably but one disease, 
European foul brood; the “‘non-stinking foul brood”’ is the same as is 
now known as American foul brood, and the samples which were 
reported as containing no bacteria together with those which were 
