968 EXPERIMENT STATION RECORD. 



spread with spores and dried were exposed to direct sunlight in Feb- 

 ruary. The temperature during the experiment varied from —12 to 

 — 22° C. After exposure, the cover glasses were placed film side down 

 on agar and incubated at 37° C. Abundant growth took place within 

 16 hours of the different lots of spores which had been exposed to sun- 

 light for 3, 6, and 9 hours. 



Cultures of />. (f/rei-were found to live longer on agar than in li([uid 

 media. The author discusses the economic aspects of foul l)rood and 

 the losses due to this disease in different counti'ies. It was o])served 

 that after a prolonged cultivation of B. (/Irci, in which more than 

 thirty transfers had been made, the virulence of the g(^rni seemed to 

 be considerably decreased. The author ])elieves that the chief method 

 of carrying the disease from one hive to another is by bees from healthy 

 hives robbing colonies that have become diseased. A weak and l)adly 

 nourished condition of a colony of bees is considered a predisposing 

 cause to infection by foul brood. 



Remedies against foul brood are classified into three groups: The 

 stamping-out system, starvation methods, and treatment by chemicals. 

 In the stamping-out system, affected bees, combs, and frames must be 

 destroyed and the hives thoroughly disinfected. By the starvation 

 method, combs are removed and the bees allowed to fast for 2 days or 

 more, after which they are introduced to clean new combs and fed on 

 sirup prepared from hot water mixed with honej^, nutmeg, and saffron. 

 Since this original starvation method was proposed, various modifica- 

 tions of the method have been elaborated and applied in the Ignited 

 States and Europe. In the use of chemicals for the treatment of foul 

 brood, the object is to secure a substance which will destroy or pre- 

 vent the gi'owth of IJ. alvei in the bees without injuring the latter. 

 In this way the following substances have been used: Carbolic acid 

 1 :600 of sirup; or a deciliter of carbolic acid in sirup and a liter of 

 water thoroughly shaken together; salicylic acid, salicylic-acid vapor, 

 camphor, thyme, thymol, carbolic acid and tar, creolin, eucalyptus, 

 naphthol /?, naphthaline, and formic acid. In experiments with these 

 substances the various chemicals have been used both as external anti- 

 septics and in the food of bees. Formic acid probably hel])s th(^ bees 

 to ward off an attack of foid brood. This substance is a natural con- 

 stituent of honey, and it was found that the spores of the //. <(lr)4 

 develop less vigorously after cultivation on agar containing foi-mic 

 acid. 



The author conducted experiments on the use of drugs for prevent- 

 ing tlui disease. Two small hives containing strong healthy swarms 

 were selected for this purpose and placed side by side. Hive A was 

 given spores of B. ah)ei in sirup containing ^ gm. of naphthol /? to a 

 liter, while hive B was fed spon^s in sirup containing from 1.6 to 1.8 

 cc. of formic acid to the liter. The spores wei'c poured into the 



