40 THE BACTEEIA OF THE APIAEY. 



Four series of agar plates showed apparently no diminution in 

 the number of bacteria present. 



Further experiments were made by using Novy's anaerobic jar 

 (a very tight chamber) as a chamber in which to put the diseased 

 brood combs and cultures. This vessel will retain the gas much more 

 perfectly than the devices made for practical use in the apiary. 

 Treatment of brood in this jar by recharging with the gas resulted 

 usually in complete disinfection after 2 days. Agar plates con- 

 taining spores and cheese cloth on which cultures were spread and 

 dried were disinfected after a short length of time by the applica- 

 tion of formaldehyde gas. 



From the experiments made the conclusion can be drawn that 

 formaldehyde gas is a good disinfectant, but that it penetrates very 

 slowly and that 24 hours' application of the gas to the combs, as 

 usually applied, is not sufficient to kill all the spores in the decayed 

 larvae (27). 



AMERICAN POUL BROOD. 



The diseased condition which we shall call American foul brdod 

 and the micro-organism found constantly present in the diseased and 

 dead larvae, which we shall call Bacillus larvae, were, for convenience, 

 referred to, respectively, as " X Brood " and Bacillus "X " in a 

 former report (27). This disease has been called " foul brood " by 

 many bee keepers in this country and in other countries as well. It 

 is the diseased condition with which Mackenzie, Harrison, and 

 William R. Howard were working largely, if not altogether, in their 

 investigations of foul brood. The disorder is, as a rule, dreaded less 

 than European foul brood by the apiarist, yet in the aggregate the 

 bee industry suffers enormous losses from the trouble. The general 

 character of the diseased brood is so much like that of foul brood 

 that the two may be easily confused by those unfamiliar with the 

 variety of appearances which one finds in each disease and a few 

 characters which are differential. Therefore it is not strange that 

 the mistaken diagnosis should be made from the symptoms mani- 

 fested by these two diseases. When, however, European foul brood 

 and American foul brood are subjected to a bacteriological exami- 

 nation, the diagnosis is easy. Experts when comparing specimens 

 of the two diseased conditions are able to see a difference in the 

 gross appearance. 



Symptoms. 



The symptoms are given by Dr. E. F. Phillips in Circular No. 79, 

 Bureau of Entomology, as follows : 



The adult bees of an infected colony are usually rather inactive and do little 

 toward cleaning out infected material. When the larvas are first affected they 

 turn to a light chocolate color, and in the advanced stages of decay they become 



