62 



experimenters made numerous attempts to infect healthy bees with Nosema, 

 and these were usually very successful so far as transmitting Nosema and 

 killing the bees were concerned. But the bees had never any real opportunity 

 of displaying the characteristic symptoms of Isle of Wight Disease. The bees 

 experimented on were either small lots confined in cages or bell-jars, or full 

 stocks kept in confinement. Those kept in cages and fed on fresh spores died 

 very rapidly indeed, usually in little more than a week after infection. A 

 heavy spore infection was noted as early as the fifth day. "When confined 

 merely to an infected cage, or when fed on spores some months old, the bees 

 lived longer (27 days), but were believed to have died of Nosema in the end. 

 Controls were kept alive as long as 21 days ! In two cases the bees died 

 rapidly, but Nosema was not found. The fact is that it is not easy to 

 understand the behaviour of bees confined in cages. I have kept a queen 

 and her attendants for weeks at a time in my pocket without any signs of 

 trouble. On other occasions when the conditions were apparently similar the 

 bees died in a day or two, sometimes within a few hours. Queenless bees in 

 a cage would probably worry themselves to death in quite a short time. 



The first experiments on full stocks were carried out in 1910 in Scotland. 

 A hut was divided with double partitions of muslin into four compartments, 

 9 feet by 3J feet, and a healthy stock placed in each compartment in July. 

 The stocks in I., II. and III. each received an addition of diseased bees, 

 while IV. was kept as a control. The bees in I. were all dead by 11th 

 March, and the dead bees contained numerous spores of Nosema. But this 

 stock had shown " no obvious signs of disease " ! (p. 87). No. II. died off by 

 the end of March after suffering from dysentery, and "spores of Nosema^ apis 

 were found in moderate numbers." No. III. was a stock of hybrids, and the 

 bees remained well and active, till they died of starvation about the end of 

 March. No spores were found. The control stock in No. IV. remained 

 "strong and well till the middle of March, after which they gradually died 

 off." No spores were found in the bodies. Two things are noteworthy: (1) 

 there is no proof that any of the stocks suffered from Isle of Wight Disease, 

 and (2) the infected bees survived practically as long as the control bees. 



Similar experiments were carried out at Cambridge in 1911 by Graham- 

 Smitli and Bullamore. Compartments 9| feet by 3| feet were used, and six 

 stocks of bees were placed in these on 18th May. I. and VI. were control 

 stocks. The former died out on 17th July, and the latter on 17th October, 

 a difference of exactly three months. The fact that of two similar stocks, 

 one survives just twice as long as the other under confinement, indicates how 

 little reliance can be placed on these experiments. Neither stock gave 

 spores of Nosema. No. II. was given sealed stores from a badly infected 



