36 BULLETIN 809, U. S. DEPARTMENT OF AGRICULTURE. 



however, that the danger of infection from such hives is entirely 

 removed by carefully naming them inside. The destruction of the 

 hive is, therefore, never necessary. Chemical disinfectants should 

 not be relied upon for the destruction of the spores of American 

 foulbrood as the spores possess a marked resistance to these agents. 

 If any chemical is used, however, strong solutions of formaldehyde 

 would seem to offer some promise of being efficient. 



After disease material is removed from the hive by bees and is 

 released from them the chances that a bee will come in contact with 

 the contained spores again is comparatively slight. Furthermore 

 such spores must withstand certain agencies in nature which tend 

 to destroy them, thus decreasing the chances still further that disease 

 will result from them. If exposed to the direct rays of the sun the 

 spores will be destroyed more or less readily (p. 29). Much less is to 

 be expected from fermentation (p. 31) or drying (p. 29). Should the 

 spores reach the soil or running water the likelihood that bees will 

 come in contact with them and carry them to the feeding brood is 

 indeed slight. Should the spores reach the water supply of the bees 

 and should this supply be a stagnant or slow-moving body of water, 

 the chances naturally would be somewhat increased. 



Experiments in which queens taken from diseased colonies were 

 introduced into healthy ones were not kept under observation for a 

 sufficiently long period to justify a definite conclusion as to the prob- 

 ability of the disease being transmitted by such queens, but the data 

 secured indicate strongly that the danger of transmission in this 

 way has been overestimated at times. The favorable results ob- 

 tained by beekeepers using the shaking treatment should tend to 

 allay fear in regard to the transmission of the disease by this route. 

 Indeed the facts thus far obtained suggest that the transmission of 

 the disease by way of the queen should not be expected. 



The spread of the disease by means of the clothing or hands of the 

 apiarist is not to be feared especially. The hive tool, if brought in 

 direct contact with dead larvse in testing for the presence of disease, 

 might serve to transmit infection, but during the usual manipula- 

 tions it would not. The practice sometimes followed by beekeepers 

 of thrusting the hive tool into the soil to clean it would seem to be a 

 safe procedure. Washing the hands with water instead of disinfec- 

 tants is more convenient and is sufficient. Reasonable care should 

 be taken, of course, that the water used does not become or reach 

 the water supply of bees. 



DIAGNOSIS 



American foulbrood is the easiest of the brood diseases to diag- 

 nose. Methods by which this can be done in the laboratory are 

 given in an earlier publication (16). The diagnosis as a rule can be 



