The Sterilization of American Foulbrood Combs 17 



tion of the cell space is often filled with air. Of course the solution, 

 particularly an alcoholic solution when used with open cells, forms a 

 film on the surface of the cell around the bubble, as has been de- 

 scribed by Demuth (P), and thus comes in contact with the larval 

 remains. In the case of capped cells, however, under normal atmos- 

 pheric pressure this bubble can not get out, and only a small quan- 

 tity of liquid can gam access, in some cases probably not enough to 

 form this moist film. 



It was thought at first that this vacuum treatment might be a 

 satisfactory method of disinfecting foulbrood combs, but aside from 

 the cost of apparatus it was found that after this procedure it was 

 practically impossible to remove the disinfectant from the sealed 

 cells, even by means of centrifugal force, particularly from those 

 whose cappings had not been broken, until after removal of the cap- 

 pings. Liquid in the perfectly capped cells evaporated slowly, and 

 a deposit of solid paraformaldehyde would probably remain in them. 

 This residue has been found objectionable if not positively detri- 

 mental to the bees when combs with such a residue are given to a 

 colony. Cultures made from a few combs so treated and allowed to 

 dry for a long time gave completely satisfactory results, no growth 

 being obtained from any cells, either open or sealed. For combs 

 from which all cappings have been completely removed this method 

 of filling all the cells with liquid, thus assuring actual contact of all 

 cell surfaces and cell contents with the water disinfectant, shoud be 

 satisfactory, provided a simple and inexpensive vacuum apparatus 

 can be devised. 



PERFORATION OF CAPPINGS 



It seemed evident that because of the greater impermeability of 

 many of the cappings the diseased material in some of the sealed 

 cells of the immersed combs was prevented from coming in contact 

 with sufficient disinfectant to kill the spores of Bacillus larvae in the 

 infected remains. A preliminary method of perforating brood cap- 

 pings was tried. By means of a blunt needle holes variable in size 

 and intended to resemble perforations in cappings made by the 

 bees, were made in all cappings, through which the solution might 

 be able to enter the cells more readily. - Series of samples of combs 

 with cappings perforated in this manner were treated in both alco- 

 hol-formalin and water-formalin solutions, some for 24 and others 

 for 48 hours, as well as in two lots of soap solution for 48 hours. In 

 the 24-hour tests with alcohol-formalin solution, of the 20 scales cul- 

 tured (Table 8) 5 gave positive growths of B. larvae, whereas in the 

 case of the water-formalin solution only 1 scale from a perforated 

 cell, of 20 cultured (Table 10), showed a few germinated spores. 

 In the 48-hour tests with alcohol-formalin solution only 1 scale 

 showed growth out of 20 cultured from perforated cells (Table 7). 

 In the 48-hour tests with water-formalin solution 2 scales, of the 

 20 cultured from perforated cells, showed a few germinated spores 

 (Table 9). In tests with soap-formalin solution and perforated cap- 

 pings (Table 1) the contents of all such cells were apparently ster- 

 ilized as far as this particular experiment was carried. These results 

 indicate that in the case of both solutions the action was aided by 

 perforating the cappings, but in a few instances the sterilizing action 



