BEES IN COLONIES AFFECTED BY EUROPEAN FOULBROOD 25 



spores, are predominant as described by White (12) and McCray 

 (4). Soon the putrefactive spore- forming organisms increase in 

 number, Bacillus alvei'^ being the one most commonly found. This 

 is seen particularly in the case of the more mature larvae, which when 

 dying extend more or less irregularly in the cells, becoming the gray- 

 ish brown slimy masses which develop into the dark brown granular 

 rubbery scales. This fact has been observed for a long time in the 

 many samples which have been received for diagnosis. A partial 

 description of these scales and of the presence of Bacillus alvei in 

 them is given by McCray and White (5), but the experimental 

 observations described in this paper added to diagnostic observations 

 show that this condition is generally much more pronounced and 

 common than described by these writers from laboratory observa- 

 tions. The rapid increase and peculiar process of decomposition of 

 Bacillus alvei^ after the death of the larva, often to the exclusion of 

 all other organisms, accounts for this abnormal appearance. In the 

 case of American foulbrood, almost never is any other organism 

 found associated with the disease but Bacillus larvae^ the cause of 

 the disease. This accounts for the constancy of the symptoms as 

 compared with the variation of symptoms in European foulbrood 

 where there may be several secondary invaders. 



Furthermore, in making the smears of the diseased larvse upon 

 cover glasses, the peculiar whitish saclike extrusion of the larval in- 

 testines was often noticed on crushing the larvse preparatory to smear- 

 ing, which White (10) describes as a gross diagnostic character. 

 When this sac was removed and smeared separately, it was always 

 found to be heavily loaded with Bacillus pluton. Therefore it is safe 

 to assume that the intestinal tract is the primary focus of infection, 

 while the secondary putrefaction takes place mostly in the body tis- 

 sues of the dead larva. 



Coincident with the microscopic examination of larvse, several ex- 

 aminations were made of the contents of the ventriculus, rectum, and 

 in a few cases of the honey stomach and mouth parts of bees. These 

 bees were presumably nurse bees taken from diseased combs, some in 

 the very act of sucking up the juices of dead diseased larvse. Al- 

 though insufficient observations were made to give conclusive evidence, 

 some interesting information was obtained. 



As may be seen from Table IV, the number of cases where Bacillus 

 pluton or other organisms associated with infectious material were 

 found in the intestinal contents is not very large. However, of more 



1 Bacillus alvei originally was supposed to be the primary cause of European foulbrood, 

 but has been proved by White and others to be only a common secondary invader. Bacil- 

 lus alvei has purely putrefactive functions. From its cultural and biochemical character- 

 istics, Bacillus alvei apparently belongs to the common Bacillus suhtiUs (hay baclll\i») 

 group of spore-forming organisms, all having mainly putrefactive functions. 



