92 



VI. 20th June. — Fresh spores of Nosema were, on this date, mixed with 

 honey and fed to a number of bees in a small cage. On the 26th several of 

 the bees were killed, and an examination was made of the alimentary canal. 

 Planonts were seen in very large numbers. A further examination on the 

 80th revealed the presence of both planonts and meronts. Spores were not 

 seen. 



In connection with the foregoing experiments control lots of bees were 

 in most cases kept. Further we have had a very considerable experience with 

 caged bees under the same conditions as those of the experiments. We have 

 not been able to detect significant differences in mortality amongst such caged 

 bees. No conclusions are therefore drawn with reference to the cause of death. 

 Our experience is that captivity in small cages without a queen is eventually 

 fatal to the healthiest of bees. 



With regard to the behaviour of the bees while under experiment, it 

 was not possible to decide whether Isle of Wight was present. The 

 condition of the intestine which we have learned to associate with Isle of 

 Wight disease, and which we find has been described by Imms {Jour. B. of A., 

 xiv. pp. 133-4), has never been observed in those caged bees. 



The experiments numbered II.-IV. were made in September and January 

 with spores obtained from bees which died in June. These dead bees were 

 kept in a laboratory cupboard under ordinary conditions, and the results 

 would suggest that in some instances at least the vitality of the spore is 

 brief 



Conclusions regarding Eelation between N"osema apis and 

 Isle of Wight Disease. 



Our main conclusion regarding Nosema apis is that so far we have 

 been unable to recognise any causal relation between the presence of this 

 parasite and the disease. We have found it to be present over prolonged 

 periods in healthy stocks, while we were unable to find it in other stocks 

 in the apiary, nor did Isle of Wight disease spread under these conditions 

 although various races of bees were present. Deliberate infection of a stock 

 with Nosema did not produce the disease. It is well established also that 

 the disease occurs where the parasite cannot be found. We have numerous 

 instances of this on Deeside. 



From known facts regarding Nosema in other countries, e.g. in Germany 

 and in Victoria, Australia, it appears that Nosema apis is just as common in 

 healthy bees as in diseased. They are practically all " parasite earners." 



