BURRI, JANUARY, 1906. 69 



very near the combs, or, better, the removal of a larva and testing 

 it. He calls attention to the fact that "foul brood" (American foul 

 brood) and "sour brood" (European foul brood) have probably 

 often been confused by bee keepers of little experience and placed 

 under one name, "foul brood." 



Another point of dilForcnce between "foul brood" and "sour 

 brood," as pomted out by Burri, is in relation to the consistency of 

 tho dead larvoe in the two conditions. In "foul brood," he says, a 

 luiiform ropy mass is all that remains of the decaying larva dead of 

 the disease, while in "sour brood" the chitinous covering of the 

 decaying larva permits its removal as a whole from the cell. 



Besides the odor and consistency of the dead brood, Burri refers 

 to the color as a third characteristic that serves to aid in the dilfer- 

 entiation of "foul brood" and "sour brood." He writes that the 

 larvjB of "foul brood" are cream colored soon after the development 

 of the bacteria has begun, but later are a pale coffee brov^n, and finally 

 a dark brown. In "sour brood," he says, the larvae become discol- 

 ored. At fu-st they are a dirty yellow. The dry scales are less black 

 than those of "foul brood." 



Burri received samples which were reported to him to be "black 

 brood." The older larvae seemed to be affected and the microscopic 

 and cultural examinations gave negative results.. This strongly sug- 

 gests that this is not the condition to which the term "black brood" 

 has been referred in America. No conclusion was reached by him 

 as to the cause of this trouble. Certain differences were noted by 

 Burri between the descriptions by Dadant of the different brood dis- 

 eases and his own observations. It is not difficult to understand why 

 such differences should exist when one recalls that so many descrip- 

 tions of the brood diseases in the past by Americans have been based 

 largely upon faulty work. 



Further on in his paper, Burri gives the microscopic findings and 

 describes the gross appearance of a few larvae taken from each of the 

 eight samples of sour brood which he examined. He mentions in 

 "sour brood" the yellowish color of the larvae, the uncapped cells, 

 and the presence of rather long rods. Short rods were also found, 

 resembling in morphology Bacterium, guntheri. On account of tliis 

 similarity, in recording the presence of this latter species, Burri has 

 referred to it as the "^wnfAen-forms." These facts concerning the 

 gross appearance of the microscopic findings in "sour brood" suggest 

 strongly that the condition is the same as the foul brood of Cheshire 

 and Cheyne (European foul brood). 



In summing up the results of his study on "sour brood," Burri 

 emphasizes two observations: First, that there is a form of disease 

 found all over Switzerland which possesses the characters mentioned 

 for "sour brood"; and, second, that in the condition there is a certain 



