146 



No. 6. Appearance of Nosema in an Isolated Stock —The 

 following is a continuation of the history of the stock, whose 

 initiation as an experiment is recorded in a previous paper. {Proc. 

 Roy. Phys. Soc, 191 6, p. 57.) 



On the 20th February 1916 this stock was found reduced in 

 numbers and short of food. There were signs of dysentery about 

 the frames. Bees examined were found to be infected with 

 Nosema. Instructions were given for close observations to be 

 made on the stock. 



During March the weather was cold, but the stock seemed to be 

 doing fairly well and dysentery was not so marked. 



On the 3rd April three boxes of bees from it were sent to 

 Aberdeen. Nine bees were alive on arrival and were kept under a 

 bell jar in a sunny position till the last bee died on the nth. All 

 the dead bees were examined and found to contain spores in great 

 numbers. The living bees also were found to be infected, and one 

 of those which flew upon release showed a complete infection of 

 the chyle stomach, not a single healthy cell being visible. At 

 the end of the month the stock was reduced to four frames 

 of bees. 



On the 7th of May the queen was found dead on the floor of 

 the hive. She was found heavily infected with Nosema spores. 

 The stock was very weak in numbers, and samples examined 

 showed an extremely heavy Nosema spore infection. 



The chief points of note regarding this stock are these. The 

 colony was isolated from all other hive bees ; it was presumed to 

 be free from Nosema when this took place, although we cannot 

 be certain that this was the case. As already reported {Op. cit., 

 p. 52), it was fed with stores contaminated with Isle-of-Wight 

 diseased bees, and there is no record at any period of its history of 

 Isle-of-Wight disease symptoms. The colony died out three months 

 after the infection with Nosema was detected, the bees at the end 

 showing typical appearances in the intestine of heavy Nosema 

 infection. Dysentery was also a feature in this case. 



In view of the fact that loss of the queen, as we record later, is 

 an occurrence liable to ensue on Nosema infection, it is worth 

 recalling that twice during the history of this stock, viz., in the 

 winter 1914-15 and in the summer of 1915, this stock became 

 queenless. Examinations for Nosemav/cre not being made during 

 the period within which these queens were lost. 



Further Experiences of Nosema. — In addition to the foregoing, 

 we have on frequent occasions discovered the presence of Nosema 

 in stocks of bees under circumstances which prevented us from 

 making continuous studies of the stocks themselves. We have 

 found, e.g., that this parasite is probably more common amongst 

 Italian bees ; and further, our observations lead us to the view that 

 such bees are largely tolerant of the parasite under ordinary 

 conditions. In this connection there must be borne in mind the 

 significance of such infected bees in Great Britain as nurseries and 

 disseminators of Nosema. 



The foregoing account of the course of Nosema infection in the 



