Sept. 1, 1932 Commercial Honey and Spread of American Foulbrood 279 



from contagious or infectious diseases of bees, but in the other 44 counties Ameri- 

 can foulbrood lias been present. 



An average of 668 beekeepers have been visited each year and 38,661 colonies 

 examined with the result that an average of 430 colonies, or 1.11 per cent, have 

 been found to be diseased. 



American foulbrood is found now in only 23 counties, 21 of the 44 counties 

 having been cleaned up. In 12 of the counties where disease occurs, only 30 

 colonies were found to be infected out of 7,642 examined — less than 0.4 of 1 per 

 cent. Six counties had one diseased colony each. 



About 40 per cent of the beekeepers and 60 per cent of the colonies are rein- 

 spected from year to year; the remainder, being free of disease and considered 

 out of danger, are dropped and "new territory" is taken over and examined for 

 presence of foulbrood. By "new territory" is meant beekeepers and their 

 colonies visited and inspected for the first time. An average of 228 diseased 

 colonies are discovered each year in "new territory." This is 1.6 per cent of the 

 total number of colonies examined in this territory. 



The reinspection which has been made in the counties where disease has been 

 present shows that there have been both gains and losses. But a net gain has 

 resulted which has averaged 21 beekeepers and 368 colonies freed from American 

 foulbrood and quarantine annually. 



From these facts it is easily seen that definite and really rapid progress in 

 eradicating the disease is being made. Rarely do our inspectors find new out- 

 breaks of disease that can not be traced to careless beekeeping methods, bees 

 robbing infected and weakened colonies, or to the use of old and infected equip- 

 ment. 



It is not my intention to imply that honey is not a carrier of American foul- 

 brood. The above evidence simply indicates that the honey which has been 

 imported into Texas has not been as dangerous a source of disease to bees as is 

 sometimes thought. 



Practically no work has been reported on the microbiology of 

 honey other than that in connection with the spoilage of honey 

 through fermentation by yeasts {19, 21), and no work appears to 

 have been done on the Bacillus larvae spore content of commercial 

 honey. In 1925 the writer undertook to devise a method for demon- 

 strating, at least qualitatively, the presence or absence of spores of 

 B. larvae in honey and their significance in relation to the results of 

 the spore-feeding experiments. Difficulties were encountered in 

 obtaiaing cultures of B. larvae from honey. It was impossible to 

 obtain vegetative growth of this organism, even when a considerable 

 number of spores had previously been added to honey, because of the 

 difficulty of eliminating contaminating organisms that developed 

 rapidly in the honey, completely overgrowing any possible vegetative 

 growth of B. larvae before it could get well started. Therefore, 

 methods of concentratiag the spores from the honey and of identifying 

 them by means of microscopic examination were attempted. Because 

 spores of B. larvae have a characteristic appearance in stained smears 

 {20, -p. 9), it was assumed that this method might give at least tentative 



6V1(1gI1C6 



METHODS OF,PE0CEDURE 



The first method attempted was the filtration of honey diluted 

 with water through a membrane of ether-alcohol collodion or through 

 filter paper impregnated with an acetic acid solution of collodion 

 {9). Apparatus was devised in which both suction and pressure 

 were tried in this filtering process. Stained smears were made of the 

 sediment' retained on the surface of the filter. In several cases 

 spores of Bacillus larvae were observed in stained smears of the sedi- 

 ment filtered out of honey known to have a large spore content. 

 However, with honey containing fewer spores it was found impossible 

 to concentrate them on a small enough area of filter in sufficient 



