48 Proceedings of the Royal Physical Society. 



as a swarm from the South of England in June 1914. They had been examined 

 on 30th June, and again on 13th July, and found negative as regards Nosema 

 spores and young stages. There were no other hive bees within a radius of 

 5 1 miles. 



On 19th of August, the stock was visited and examined. It covered nine 

 combs, and clustered on the dummy. Not a " crawler " nor dead bee was to 

 be seen in front of the hive, although the weather was very favourable for 

 this. Ten bees, taken at random, were examined for Nosema, and spores 

 were found in four, two of these showing a very heavy infection. 



On 7th September, a second sample consisting of twelve bees was 

 examined, again taken at random from within the hive, and five were found 

 infected, three of them heavily. The day was fine, and there were no indica- 

 tions of Isle of Wight disease. 



On 10th October, the bees were again visited and samples taken, from 

 inside the hive as formerly. It was a fine October day, and the behaviour of 

 the bees was normal. 



On 13th October nine of the sample bees were examined. They were 

 active, flying readily, and their intestines were normal in appearance. No 

 spores of Nosema were found. On the 14th, eight more bees were examined, 

 again with negative results. On the 22nd, three bees of another sample were 

 taken. These arrived alive and active. On examination they were found to 

 have the intestine normal, and to contain no spores of Nosema. 



From the foregoing it appears certain that this stock of bees was definitely 

 infected with Nosema, but this infection failed to produce Isle of Wight 

 disease. 



The following are illustrations of numerous artificial infections with 

 Nosema carried out on small lots of bees confined in cages. 



(b) Laboratory Experiments. 



I. On 14th June 1915. — Nosema spores derived from bees of Stornoway, 

 stock No. 7 (Carniolans), were used to infect some bees taken from an 

 observation hive at Marischal College, Aberdeen. 



On the 17th, Nosema spores were found in plenty in five bees taken at 

 random from the infected lot. These spores were in alimentary canal ; no 

 intra-cellular forms were seen. Our view is that those seen were the spores 

 ingested. 



19th June i9i5.— Numerous spores were found in the colon of one dying 

 bee, and a few in the chyle-stomach. Young stages were observed in cells of 

 chyle-stomach (J. A.). 



