20 Proceedings of the Royal Physical Society. 
stocks in Germany, and that stocks containing the parasite winter well, 
and display no signs of dysentery or May-pest. He admits that WVosema 
may be pathogenic, but believes that disease makes its appearance only 
when the stocks are weakened by unfavourable conditions. In the season 
1909-10, he carried out an experiment with 30 stocks of bees all strongly 
infested with Nosema. In the spring three colonies showed dysentery ; two 
had a heavy loss of bees; one died outright, apparently from starvation. 
The three dysenteric colonies recovered. The remaining 24 stocks wintered 
well and developed normally in spring, except that some of the colonies — 
displayed “ Mackrankhewt” without great loss. It was easy to prove the 
presence of Nosema in all the colonies, and at times the parasite was present 
in enormous numbers. Only the bees newly hatched were at all times free 
from infection. The stocks with May disease got over it and became 
prosperous in summer. MHeberle, discussing this experiment in the American 
Bee Journal of May 1914, remarks that ‘‘ Dr Maassen’s experiment tends to 
show that a Nosema infection is not necessarily very disastrous, since even 
the 24 colonies that were taken through the winter did not show an unusual 
number of dead bees. They wintered well, and developed normally in 
spring. Only 10 per cent. of the Mosema-infested colonies developed 
dysentery, and even these got over it, and became useful colonies.” 
In Australia, Canada, and the United States there is a disease of adult 
bees, known as “paralysis,” with very much the same symptoms as Isle 
of Wight Disease. On the continent a similar disease is known as 
‘“ Maikrankheit” or May Disease. In Australia the disease has long been 
studied by Mr F. R. Beuhne, B.Sc., who is quoted on page 51 of the report 
for 1912. He had stated that Nosema had been proved to occur all over 
Victoria, and that “many specimens of paralysis of the most pronounced 
type were entirely free from Nosema.” In Cleanings in Bee Culture for 
December last, he writes again: “ You can find hundreds of colonies with 
the Nosema parasite and no symptoms; and any number of others with 
all the symptoms of paralysis but no Nosema parasites in the bees.” The 
reply of the Cambridge workers is that by “ Nosema” Beuhne means “ spores 
of Nosema” (page 52). They suggest that in all cases of disease in which 
he could not find spores, Vosema must have been present in the “ young stage.” 
In reply to the statement that “you can find hundreds of colonies with 
Nosema, and no symptoms,” the Cambridge workers suggest that Victoria 
must contain a large percentage of stocks which consist of parasite carriers. 
But to assume that there are hundreds of stocks composed mainly of parasite 
carriers seems to be putting somewhat of a strain upon the term. 
3. If Nosema be the cause of Isle of Wight Disease, it ought to be possible 
to produce the disease by a pure infection of Nosema spores. The Cambridge 
