ci60 Scientific Proceedinc/s^ Royal Dublin Society. 



or (c) oil the surface of the bees, Ijy spiinlding the hive with some substance 

 whicli would come into contact with the peripatetic gravid females, and thus 

 prevent newly emerged bees from becoming infected; or finally, {d) to find 

 some way of preventing clean stocks of bees from becoming infected. 



John Reiinie and various bee-keepers have tried many methods. The former 

 mentions in one of his papers that many fumigants will kill the mites in 

 experimental chambers : unfortunately Rennie does not appear to have given 

 a list of these substances in anj' of his published work. In 1923, Wood 

 announced that Rennie had found what might be assumed to be a cure for 

 the disease, and, in his letter to an English bee journal, mentioned the name 

 of an Aberdeen chemist from whom, for the sum of 2s. 6d., bee-keepers might 

 obtain samples of this secret substance. In various bee journals from time 

 to time "curas" for Isle of Wight bee disease have been annoiuiced. We 

 ourselves have received visits from various bee-keepers who claimed to have cures 

 for the disease. 



We have thought it right to publish all our findings, in order that future 

 workers might have the assistance of knowing our methods and our failures. 

 Some, or all, of these methods may have been tried by Rennie — ^we do not know. 

 We have not had Rennie 's secret treatment analysed, but we have examined 

 Irish bees which were said to have been treated with this cure, and wei'e 

 found still heavily infected. We do not wish to say that Rennie 's treatment 

 is not helpful ; we state, however, that it is probably only an alleviative, and 

 not a cure. 



Some of the "cures" are substances which are slightly toxic to the bees, 

 and by giving the coup de grace to badly diseased and weakened individuals 

 lessen the incidence of infection of the newly-emerged bees. So far as we are 

 aware none of these substances does more than alleviate the disease : this, 

 however, is a step in the right direction, but does not prevent the spi'ead 

 of the disease, and may leave the stock in a weak condition. The danger 

 of such half -measures is that these stocks are a constant menace to clean hives 

 in the neighbourhood. 



At Trinity College, Dublin, we set up an apiary for diseased bees, and 

 have had six stocks under continual observation. Besides this we have been 

 able to examine and observe at intei'vals many other stocks, both diseased and 

 healthy. 



We arranged our experiments with the object of trying to affect the haemocoel 

 fluid of the I^ees, and thus to make the conditions unsuitable or toxic for the 

 mites. Two stocks were used as controls, one being at Trinity College. The 

 winter montlis, during which the experiments were carried out, were very 

 favourable for working out percentages of infection, for noting fluctuations 

 if such occur, and so on, because no new bees were emerging. 



Every week we examined large numbers of bees, and were able to establish 

 the fact that very little, if any, infection of healthy bees occurs during winter 

 within the hives at the winter temperature, and during the special peliod we 

 observed the hives. This result is in accord with the fact that during winter 

 the mites breed very slowly, and in many cases not at all. 



On the time taken for hees to become infected. 



It was important to find out how soon infection of the hive may take place ' 

 after a parasitized bee has gained access to a clean stock. Prom our experiments 

 we have been able to gain a clear idea as to this. 



In April, a frame containing comb with drone brood, capped, was put into 



