Gr. W. BULLAMORB 61 



what may have been a bacterial disease was being investigated as the Isle of 

 Wight disease^. 



Tinsley (1918), in a bulletin issued by the West of Scotland College of 

 Agriculture, states that he succeeded in infecting healthy bees with Isle of 

 Wight disease by feeding them with sugar syrup in which the hquid contents 

 of the intestines of sick bees had been incorporated. In one of Dr Eennie's 

 earher experiments (1919 a) Nosema spores in candy were fed to healthy bees 

 in May. Crawling without Nosema was recorded as being present in June 

 and the bees were found dead the following January. In 1915 also, pulped 

 diseased bees were fed in honey to a stock on June 28th. The stock swarmed 

 and both lots showed crawling in October and died out. The nearest bees 

 were two miles away and remained healthy (Anderson and Rennie, 1916). 



We assume that the Nosema spores were obtained from sick bees and that 

 bacteria and other organisms were therefore unavoidably present in the 

 candy. The results obtained by Dr Rennie may thus have been due to the 

 organism that was present in the cases recorded by Tinsley. That organism 

 is unknown, but the results suggest that it was situated in the ahmentary 

 canal. 



V. Conclusions. 



Acarine disease appears to be less virulent than the disease which swept 

 across the Isle of Wight in the early years of this century. That the mite was 

 causing damage at the same time is very probable but the investigations 

 were centred on the acute and virulent disease. 



It may be that most of the stocks affected with mites, but showing no 

 symptoms of disease, die out sooner or later. But this does not demonstrate 

 the existence of a new disease. It merely emphasises the soimdness of the 

 older system of beekeeping which considered it undesirable to retain any 

 stock after the third season, the less desirable colonies being sulphured at an 

 earlier period. 



Although it may not be the cause of the Isle of Wight disease the dis- 

 covery of the mite is of economic importance, reveahng, as it does, one of the 

 causes of the failure of modern beekeeping. Ever since the introduction of 

 the "humane" system which saved the redundant bees and distributed them 

 as "driven bees" throughout the length and breadth of the land, there has 

 been a steady increase in disease which has helped to render the industry of 

 honey production an unprofitable one. Before the rise of the Isle of Wight 

 epidemic the losses were attributed usually to foul brood, although there was 



^ The difficulty in classifying bee disease by symptoms is well shown by the following instance. 



While the work on Nosema in its relationship to Isle of Wight disease was being carried out 

 at Cambridge there ensued a heavy mortality of humble-bees which was found to be associated 

 with the presence in the Malpighian tubes of a protozoon closely resembling Nosema. In the 

 year immediately past a similar mortaUty has been noticed in humble-bees, but the protozoon 

 could not be found. The organism accompanying the mortality in 1921 was a nematode worm 

 Sphaerularia bombi which undergoes development in the body cavity of the bee and eventually 

 gives rise to huge numbers of larvae. In both years, the symptom of the trouble was inability to fly. 



