2 Department Circular 284, U. S. Dept. of Agriculture 



solid paraformaldehyde, came to a similar conclusion. The great 

 difficulty always was found to be the holding of the gas in contact 

 with the combs, without leakage to the outside, for a sufficiently 

 long time to allow for this slow penetration and the complete 

 sterilization of all the spores of Bacillus larvae. 



Late in 1922 the apparently successful use of a new liquid disin- 

 fectant for treating infected combs was announced by J. C. Hutzel- 

 man, of Glendale, Ohio {11). The disinfectant is composed prima- 

 rily of 20 parts of formalin solution to 80 parts of specially denatured 

 alcohol. The infected combs are placed in a tank and completely 

 immersed in this liquid for 48 hours. At the end of that period the 

 combs are removed and as much as possible of the excess liquid is 

 removed from them, an extractor being used when available. They 

 are then allowed to dry, until no odor of formaldehyde remains, 

 before the combs are returned to healthy colonies. The use of 

 alcohol as the carrier for the formaldehyde, which is the active 

 sterilizing agent in the solution, is based, according to Hutzelman, 

 upon two properties. Since alcohol is a liquid of low surface tension 

 the solution is supposed to enter readily and permeate thoroughly 

 all empty spaces in the combs. Further, it is claimed that this alco- 

 holic solution, because of its solvent action, penetrates the wax and 

 propolis, as well as cells filled with pollen, all of which may contain 

 spores of Bacillus larvae. Hutzelman is of the opinion that the 

 sterilization of all of these is necessary for the successful disinfection 

 of infected combs. He has also stated that while all sealed honey 

 cells must be opened, sealed brood cappings need not be removed if 

 the combs are treated for 48 hours, as the brood cappings are porous 

 and are penetrated by the alcoholic liquid. Much credit is due 

 Doctor Hutzelman for thus being the first to demonstrate the prac- 

 tical possibility of holding the formaldehyde in more or less direct 

 contact with the diseased material in combs infected with American 

 foulbrood for a sufficiently long period to kill the spores of B. larvae. 



In June, 1924, Dan H. Jones (i^), of Ontario, Canada, reported 

 the results of some cultural experiments with various disinfectants, 

 including the alcohol- formalin and also water-formalin solutions. 

 He states that the alcohol-formalin solution 



is effective in killing the spores of Bacillus larvae in 24 hours in foulbrood 

 affected combs when it comes in contact with the larval scales in open cells. 

 In case of capped cells, however, it would appear that 48 hours' immersion is 

 essential. 



Concerning various mixtures of water and formalin he says : 



Formalin diluted with water in as high a dilution as 15 per cent formalin to 

 85 per cent of water is effective in destroying in 24 hours the spores of Bacillus 

 larvae as they occur in larval scales in open cells. Although in our experiment 

 a 48-hour immersion in the formalin and water mixtures gave us a hundred 

 per cent sterile results in the cultures made from capped cells, we can scarcely 

 expect that such would always be the case, as the porosity of the cell caps 

 varies considerably. 



In a recent article Jones (15) gives a further report of investiga- 

 tions with water-formalin solution, as indicated by the following 

 table from his paper: 



