NOSEMA-DISEASE. 29 
repeated. Out of 138 bees in one set of four cages 125 (91 per cent) 
were dead at the end of one week. In the other set of four cages out 
of 136 bees confined 98 (72 per cent) were dead at the end of a week. 
On December 8 a check experiment was begun. In each of two 
cages bees taken from healthy colonies were confined and kept at 
room temperature. At the end of one week out of 59 bees confined 
5 (8 per cent) had died. 
Out of a total of 472 diseased bees confined 393 (83 per cent) were 
dead at the end of one week, while out of a total of 59 healthy bees 
kept under similar conditions only 5 (8 per cent) were dead at the 
end of a week. Although such experiments are subject to great 
variation and should be repeated many times for definite results, yet 
the difference between 83 per cent of loss in the case of infected bees 
and 8 per cent of loss in the case of healthy ones is sufficiently great 
to justify the conclusion that the heavily infected bees under the con- 
ditions of the experiment possessed less endurance than the healthy 
ones. These results indicate that weakness in a colony may result 
directly from infection among the workers. 
Throughout the investigations which have been made on the dis- 
ease, therefore, evidence has been obtained indicating that weakness 
results not from the infection of the queen, drones, or brood, but of 
the workers. 
RESISTANCE OF NOSEMA APIS TO HEATING. 
NOSEMA APIS SUSPENDED IN WATER. 
Preliminary results indicating the minimum amount of heating 
that is necessary to destroy Nosema apis were given in an earlier 
paper (White, 1914). Other experiments have been performed. In 
conducting the experiments a suspension was made in water of the 
crushed stomachs and intestines of Nosema-infected bees. This 
suspension was distributed in test tubes in such a dilution that the 
amount in each tube contained the infective material of from 5 to 10 
bees. The tubes were stoppered and heated at different degrees of 
temperature by immersing them in water. Colonies free from infec- 
tion were inoculated with the heated material and the results noted. 
Table VI summarizes some of the experiments made with the 
results obtained. 
