BURRI, JANUARY, 1906. 71 



other types of rods found in sour brood cells are independent organisma, 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 

 som- 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 th'e impression at first of being 

 "pure," had to be considered subsequently to be foul brood, for the second specimen 

 fi'om the same source showed unquestionably the presence of Bacillus aliel. 



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 ropLness of the 

 decaying larvas, 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. Bacterium gilntheri found in 

 sour mOk, and with these he found other rods of medium and large size. 



4. Wlien cultures were made from the larvae dead of "sour brood," 

 the guntlieriAoYjns. did not grow as a rule, but in their stead cultures 

 of Bacillus alvei appeared sometimes in pure culture. 



5. The cultivation of the guntTieri-ioTUis 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 gilntheri-iovms, in the same 

 diseased colony. "Sour brood" was reported to have been found 

 alone in one mstance. 



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 duo 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 



