1911 



GLEANINGS IN BEE CULTURE 



11 



exported to hitherto unvisited districts it 

 will still manifest itself as a serious epidemic. 



According to Mr. T. W. Cowan, the senior 

 editor of The British Bee Journal, foul 

 brood is endemic in Italy, and the exposure 

 of diseased combs to robber bees is not fol- 

 lowed by any serious consequences in that 

 country. In some parts of England also, a 

 form of foul brood is endemic. It is prob- 

 ably i^resent in all large apiaries, and can 

 best be detected in spring. Later in the 

 year, in normal seasons, the combs are 

 cleaned up. Affected colonies sometimes 

 swarm, and the surplus yield is often up to 

 the average. 



The exiieriences of American bee-keepers 

 go to i^rove that the immunity of Italian 

 bees to one form of foul brood is greater than 

 that of the black bee. Brother craftsmen 

 in Switzerland find that the susceptibility 

 of the yellow bee is greater than that of the 

 black with regard to the type of foul brood 

 present in their district. I understand that 

 these Swiss yellow bees are natives of the 

 district, and it would be interesting, there- 

 fore, to know what micro-organism is con- 

 cerned in the trouble. If it is the one to 

 which the ordinary Italian bee has a partial 

 immunity, then the explanation is that the 

 disease has recently arrived in the valley. 

 On the other hand, the trouble may be due 

 to the bacillus of a disease which has "run 

 its course" for ages among black bees, and 

 is now starting a natural-selection campaign 

 among the yellows. 



We can best understand the present state 

 of affairs by supposing that different races 

 of bees in the past have developed their own 

 endemic diseases. These diseases have been 

 kept distinct by the natural boundaries that 

 have kept the races of bees from intermin- 

 gling. Although the endemic disease of the 

 black bees {B. larvcef) may have been pres- 

 ent in the original skeps brought to Ameri- 

 ca, its mild character would not bring it in- 

 to notice. In crossing the continent, how- 

 ever, the swarms escaped for many genera- 

 tions from the selective influence of the dis- 

 ease, and the consequence has been a rever- 

 sion to greater susceptibility. 



With the introduction of Italian bees 

 came the endemic disease of Italy, and this 

 started an epidemic among the non-immune 

 blacks. Naturally the trouble would be- 

 come modified when Italian blood was sub- 

 stituted for the black strain, although both 

 races would suffer severely from B. larvce. 



The literature of bee-keeping in England 

 leads me to suppose that foul brood has long 

 been present in this country, although over- 

 looked by the early writers. With the in- 

 troduction of the frame hive it was found 

 to be far more common than was suspected. 

 The explanation is that, in the old days, 

 only the epidemics were recorded. When 

 movable combs became general the endemic 

 cases were also included. The "black " bee 

 of England is now a mongrel, and the vary- 

 ing accounts of the disease on this side are 

 probably due to the variable resistance of 

 the bees, and to the fact that the term "foul 



brood" is applied indiscriminately to all 

 varieties and mixtures of foul-brood trouble. 



At a meeting of bee-keepers, some of the 

 audience were much amused when I stated 

 that, in the struggle with disease, it was ad- 

 visable to procure queens from districts, 

 where disease was known to exist. Many 

 bee-keepers are obsessed with the idea that, 

 if we could but find some island, some dis- 

 trict, where bees are plentiful and foul brood 

 unknown, it would be a grand thing to im- 

 port stocks and queens from such a source. 

 There is no fact in our experience of disease 

 which warrants such a conclusion. Dr. 

 Dzierzon's loss of 500 colonies, and Delia 

 Rocca's description of the introduction of 

 foul brood into the island of Syra, will illus- 

 trate the terrible mortality which results 

 from a first epidemic; and it can make no 

 difTerence whether we take the disease to the 

 bees or bring the bees to the disease. 



Mr. Beuhne, the Government Inspector 

 for Victoria, Australia, informed me that 

 the same fallacy prevails there. When 

 paralysis was sweej^ing through the colony 

 he advertised for queens from an apiary 

 where paralysis had run its course. He 

 hoped by this means to confer some mea- 

 sure of immunity on his own bees; but the 

 advertisement was considered a joke, and 

 no queens were forthcoming. 



I think this question of relative suscepti- 

 bility can be well illustrated by some facts 

 relating to human disease. The Anglo-Sax- 

 on has been exposed to consumption from 

 time immemorial. It is estimated that in 

 England 80 per cent of those attacked recov- 

 er from the disease. In the cases which 

 terminate fatally, often many years elapse 

 before it incapacitates. The aborigines of 

 America, Australia, Afrria, etc., broken up 

 into hostile tribes, by this means preserved 

 a strict quarantine against the spread of 

 such a disease. When communicated to 

 any of them it often takes the form of an 

 illness which terminates fatally in three 

 weeks. In the search for immune individ- 

 uals, are we not more likely to find them, 

 among the healthy inhabitants of a crowd- 

 ed city than among these hitherto unvisit- 

 ed colored races? 



Again, there are districts in India where 

 100 per cent of the school children have the 

 malarial parasite in the blood. The relative 

 immunity to malaria of a native of such a 

 district and of an Anglo-Saxon would not. 

 be difficult to gauge. The native would 

 suffer no inconvenience. The white mark 

 would be kept alive only by regular dosing 

 with quinine. So it is with bees and their 

 diseases. The most susceptible bees will 

 come from districts that have never experi- 

 enced trouble of the kind under considera-- 

 tion. 



Although I have suggested that the Ital- 

 ian bee may owe its exemption from disease' 

 to inherent powers of resistance, there is. 

 another way in which they may have the 

 advantage. Black bees which have strug- 

 gled for generations in cold northern cli- 

 mates against long winters and unfavorable 



