61 



stocks in Germany, and that stocks containing the parasite winter well, 

 and display no signs of dysentery or May-pest. He admits that Nosema 

 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 " Maikrankheit " 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. Heberle, 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 iVbsema-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. E. 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 Gleanings 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, Nosema 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 



