39 



experiments with other colonies, that this treatment, while it 

 may not result in an absolute cure, will at any rate for a 

 time repress the disease and even check mortality during the 

 summer months. It is possible that, if the treatment be 

 begun early and be continued systematically, it may entirely 

 ward ofi the disease. There are certainly possibilities in the 

 use of this culture, and further experiments are being carried 

 out. 



Breeding to Produce Immunity. 



The real remedy for this disease lies in the production or 

 development of strains of bees immune to it. It is a well- 

 known fact that some strains of bees are highly resistant to 

 the Isle of Wight disease, and can only be caused to contract 

 it by the direct administration of considerable doses of infected 

 material. 



During the course of our infection experiments we observed 

 that certain selected colonies failed to contract the disease 

 even under conditions most favourable to infection. Their 

 powers of resistance were so marked that we decided to retain 

 them for the purpose of raising queens and the increase of 

 stock generally, and further to use them as a basis for our 

 experiments in the production of disease-resistant strains of 

 bees. In this attempt to produce immunity, purely scientific 

 methods were employed. The scheme, which started on a 

 limited scale, has now been greatly extended, so that an 

 apiary of considerable size has been built up at our head- 

 quarters, Kilmarnock. 



To determine whether the bees so bred are largely disease- 

 resistant, colonies were placed, during 1916, in the very heart 

 of districts in Ayrshire where the disease had been rampant 

 for five years, and where all attempts at re-stocking had 

 utterly failed. During last season (1917) each experimental 

 colony gave a swarm and a cast, or second swarm, and in 

 ■addition produced a good yield of honey. Up to the present, 

 the colonies are quite free from disease. 



In our efforts to raise immune strains we have experimented 

 very largely with foreign bees. Generally speaking, we have 



