NOSEMA-DISEASE. 
11 
the food within the stomach for from 1 to 3 days after the inoculation, 
but there was no evidence that the parasite had increased in numbers 
or that it had invaded the tissues. 
Nosema infection is encountered most frequently in workers, al- 
though drones and queens are susceptible. In nature it is not un- 
usual to find from 10 to 20 per cent of the workers of diseased colonies 
infected. Frequently a much higher percentage is encountered. In 
no instance has the writer found Nosema infection in drones taken 
from colonies in which the disease occurred in nature. In a few in- 
stances only were the queens that were examined from such colonies 
found to be infected. 
As a result of artificial inoculation practically 100 per cent of the 
workers of the experimental colony become infected. If drones are 
present a very large percentage of them also become infected. 
Queens in experimental colonies may or may not be found infected. 
To obtain data relative to queens a number of inoculations were 
made. Table I summarizes the experiments together with the results 
obtained. 
Table I. — Nosema infection in queens in experimental colonies. 
Date of inoculation. 
Period 
before 
examina- 
tion. 
Workers 
infected. 
Results of inoculation. 
Mar. 11, 1913 
Days. 
8 
13 
16 
19 
22 
23 
48 
53 
23 
42 
48 
53 
162 
Per cent. 
100 
100 
100 
100 
40 
50 
100 
100 
Queen not infected. 
July 12, 1913 
Do. 
Do 
Do. 
Mar. 3, 1914 
Do. 
Oct. 5, 1914 
Do. 
Oct. 19, 1914 
Do. 
Oct. 29, 1914 
Do. 
Do 
Do. 
Feb. 4, 1915 
Queen Nosema infected. 
Sept. 16, 1914 
100 
100 
100 
100 
Do. 
Nov. 20, 1912 
Do. 
Oct. 29, 1912 
Do. 
Aug. 6, 1914 
Do. 
It will be seen from the foregoing table that out of the 13 experi- 
mental colonies 9 of the queens upon examination were found to be 
free from infection while the other 5 were infected. Infection in 
the queen occurs less frequently, apparently, when the inoculations 
are made in the spring and summer than when made in the autumn 
or winter. Queens in colonies inoculated and kept at room tempera- 
ture were found infected in some instances and not in others although 
practically 100 per cent of the workers in all of them became in- 
fected. 
