The Sterilization of American Foulbrood Combs 21 



water-formalin solution. A shorter period of immersion than 24 

 hours was not tried during these investigations. 



WASHING COMBS 



In one or two instances combs have been treated with alcohol- 

 formalin solution in cold weather and allowed to dry slowly at a 

 comparatively low temperature. These, when returned to the bees, 

 have caused considerable trouble, and even loss of colonies by de- 

 sertion of the bees. Because of the retarded rate of evaporation 

 at lower temperatures, the formaldehyde, instead of evaporating, 

 undergoes a transformation to the solid and much less volatile para- 

 formaldehyde. This is probably more often true of the water- 

 formalin solution, which evaporates more slowly. When evapora- 

 tion takes place slowly, a residue sufficient to be poisonous or ob- 

 noxious to bees may remain in the cells for a considerable time. 

 Washing combs in water after treatment was tried by Jones (15) 

 to remove the odor of formaldehyde, and has been recommended by 

 Corkins (7) as a preventive against this difficulty. No observa- 

 tions in the apiary or results of cultural tests after such treatment 

 have been recorded. Several series of combs were tested, using 

 pieces from which the cappings had been cut, treating some for 24 

 and some for 48 hours, and comparing the combs allowed to dry 

 without washing with those washed in water. 



As indicated in Table 7, 50 scales were cultured from open cells 

 of combs washed in water after treatment for 48 hours in alcohol- 

 formalin solution. Of these, 3 cultures showed only a few germi- 

 nated spores of Bacillus larvae. The control series of combs with 

 open cells (Table 7) not washed in water gave no cultures showing 

 any growth. In the 24-hour tests 50 scales were cultured from open 

 cells of combs washed in water after treatment for 24 hours in 

 alcohol-formalin solution (Table 8). Of these, 2 cultures showed 

 good growth of B . . larvae and 2 a few germinated spores. The 

 control series of combs (Table 8) not washed gave 2 cultures show- 

 ing good growth, and 1 showing a few germinated spores. 



As shown in Table 9, 50 scales were cultured from open cells of 

 combs washed in water after treatment for 48 hours in water- 

 formalin solution. None of the cultures gave any growth of Ba- 

 cillus larvae. The control series of combs (Table 9) that were not 

 washed gave from open cells no cultures showing any growth. In 

 the 24-hour tests 50 scales were cultured from open cells of combs 

 washed in water after treatment for 24 hours in water- formalin 

 solution (Table 10); of these, 1 culture showed good growth of 

 B. larvae and 2 showed a few doubtful germinated spores. The con- 

 trol series of combs with open cells (Table 10) not washed in water 

 gave no cultures showing any growth of B. larvae. 



DISCUSSION 



Throughout these preliminary laboratory experiments on the 

 germicidal efficiency of the various types of disinfectants tested, no 

 solution was found which sterilized the contents of all sealed cells 

 uniformly in all of the several series of combs immersed in it. 

 This fact is probably of importance in the sterilization of brood 



