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superimpose in the same stock a Nosema infection upon Isle-of- 

 Wiglit disease. 



On the 2Sth the number of bees was reduced greatly and the 

 survivors were put up in a small cage temporarily, and subsequently 

 given a frame of Italian bees to institute another experiment. 



Means of Dissemination of Nosema Apis. 



With a view to ascertaining the degree of readiness with which 

 infected worker bees and queens may communicate Nosema to 

 others, the following experiments were carried out: — 



Infection by Contact with other Bees. — Infection of Workers. 

 — A sm.ill number of bees was given Nosema infected candy on 

 13th September 1918. Infection was confirmed by serial examina- 

 tions day by day until on the 24th there were only seven survivors. 

 At this date these were caged afresh with a number of Italian 

 bees believed by control examination of samples to be free from 

 infection, and the whole lot supplied with fresh uncontaminated 

 candy. 



On the 27th the seven black bees still survived ; one of these 

 was released and flew. It was captured later and returned to the 

 cage. The black bees died on 30th September, 17 days after 

 infection. On examination this was found to have been of a gross 

 character. 



On 9th October four of the Italian bees were dead. Only in 

 one were stray spores found; the others appeared free. One 

 remaining live bee was killed, examined, and found to be definitely 

 infected, both spores and intra-cellular stages being present. 



It would thus appear that the Italian bees underwent infection 

 by contact with the black bees, and that this was definitely 

 established within a period of fifteen days. 



Infection of Queens. — Case i. A frame with a moderate number 

 of Dutch bees was placed in an observation hive on 14th September 

 1917, and two days later a queen from a defunct Isle-of-Wight 

 stock was introduced. 



On the 2Sth, and again on 27th, candy heavily contaminated 

 with spores freshly taken from an Italian bee was supplied. The 

 bees were seen feeding upon this. At this time the bees appeared 

 quiet, but there were no signs of dysentery or other trouble, and it 

 was observed that on fine days the bees were more active and flew. 

 They were supplied with ordinary candy and also with syrup, the 

 latter of which was taken only in part. 



On nth October four bees were taken alive and examined, 

 three contained developmental stages of Nosema, and the fourth 

 was heavily infected with spores. On the following day a bee 

 found alive in the doorway lying on its back was taken, and it also 

 was found to contain enormous numbers oi Nosema spores. 



As it appeared from these examinations that this small lot was 

 extensively infected, it was decided to sacrifice the queen with a 

 view to determining whether infection in her case had taken place, 

 and at this date, i.e., seventeen days after the first supply of 

 Nosema to this lot of bees, she was taken, killed and examined. A 



