The Sterilization of American Foulbrood Combs 5 



is room for improvement which will eliminate the danger of occasional 

 cases of failure. Because of the widespread interest in this subject, 

 preliminary work was started early in 1924 at the Bee Culture Lab- 

 oratory with the purpose of making an exhaustive bacteriological 

 study of the efficiency of various disinfectants, including the com- 

 mercial alcohol-formalin solution as well as water-formalin solu- 

 tions. It was hoped that the results of the investigation by lab- 

 oratory methods would form a basis for practical work in the apiary. 

 As the work has developed, numerous difficulties have been encoun- 

 tered which indicate that the problem of the perfect sterilization of 

 American foulbrood combs is neither simple nor as yet fully solved. 

 The results given herein are of a preliminary nature, the data being 

 in some cases incomplete; but they are given for what they seem 

 to indicate. Since these investigations were started Doctor Hutzel- 

 man has taken out a patent (12) on the solution devised by him, 

 issued October 14, 1924. In the light of the issuance of this patent 

 it seems advisable to state that the United States Department of 

 Agriculture can assume no responsibility for the use of any of the 

 solutions or processes described and discussed in this paper if they in 

 any way infringe the patent. 



METHODS 



DISEASED MATERIAL FOR TESTS 



In devising methods for testing the efficiency of various disin- 

 fectant solutions, procedures were adopted corresponding as closely 

 as possible, on a reduced scale, to the actual practice of beekeepers. 

 Combs affected with American foulbrood, containing as many scales 

 as possible both in sealed cells and in open cells, were obtained from 

 various sources. From the brood areas of these combs test pieces 

 were cut approximately of the standard size of iy 2 by 2y 2 inches. 

 Glass specimen jars of about 160 cubic centimeters capacity, with 

 fitted glass covers, were used to hold the test solutions and pieces 

 of comb treated. A standard volume of liquid of 100 cubic centimeters 

 was used throughout the tests, the proportion of liquid to comb be- 

 ing approximately that in the the regular 10-frame tanks used by 

 beekeepers for disinfecting combs. Loss of liquid after each con- 

 secutive comb had been removed was made up to 100 cubic centimeters 

 with more solution before a new piece was immersed. Several 

 pieces of comb were passed through each lot of solution consecu- 

 tively, in keeping with the actual apiary practice of treating many 

 combs in the same solution. The piece of comb to be tested was 

 placed in the empty jar and fastened down with a wire spring to 

 prevent its floating. The solution was poured into the jar slowly 

 to permit the liquid more readily to enter the open cells. In accord- 

 ance with the most approved apiary practice, there was no shaking 

 of combs to aid in removal of air bubbles. The test combs were 

 then allowed to soak for 24 or 48 hours, as the case might be. No 

 immersions of less than 24 hours were tried in this series of experi- 

 ments. 



Upon removal of the pieces of comb from the disinfectant, as 

 much as possible of the excess liquid remaining in the cells and on 

 the surface of the comb was removed by vigorous shaking. Each 



