58 



with a congested mass of material, consisting primarily of pollen grains. . . . 

 Some amount of a dark-coloured fluid is present very often in the chyle- 

 stomach, but it is not distended with it." 



Mr Imms suggested no theory to account for the disease, but he re- 

 commended destruction of the affected stocks, with thorough disinfection 

 of the hives and appliances. 



Dr Maiden's researches were carried out during 1908, and his report 

 •was published in February 1909. He made a systematic bacteriological 

 examination of the alimentary canal of the bee. All bacteria observed were 

 separately investigated, and it was found that no one type was characteristic 

 of the disease. With the exception of one form, all the bacteria found in 

 diseased bees were found also in healthy bees, and just as commonly. A 

 type, called by Maiden Bacillus pestiformis apis, was, however, present in 

 60 per cent, of the affected bees, so he made pure cultures and fed these 

 to healthy bees. The bacillus was transmitted but the disease was not 

 produced, so Dr Maiden concluded that Bacillus pestiformis apis could not 

 be the cause of the trouble. 



The third and largest report, issued in May 1912, was the joint production 

 of five workers. This report extends to 143 pages, is very comprehensive, 

 and claims to contain everything of value in the earlier reports of Imms and 

 Maiden. From the point of view of this paper the most important sections 

 are IV., V. and VI., because these deal with the alleged connection between 

 Isle of Wight Bee Disease and the parasite Nosema apis. The succeeding 

 sections of the report lose a considerable part of their significance if it can 

 be shown that Nosema apis is not responsible for the disease. 



It was in 1906 that Drs Fantham and Porter discovered in diseased bees 

 from the Isle of Wight a protozoan parasite which has been stated to be 

 invariably present in bees suffering from Isle of Wight Bee Disease. In 

 1907, E. Zander in Bavaria had independently discovered the same parasite, 

 had named it Nosema apis, and had declared that it produced in bees a 

 disease which he called "malignant dysentery." (Imms states, however, 

 that dysentery is not a characteristic symptom in Isle of Wight Disease.) 



Drs Fantham and Porter have worked out the life-history of Nosema apis 

 with much care and in very minute detail. Their monograph, contained 

 in Section V. of the report, is illustrated by many drawings on a large scale. 

 The organism produces a characteristic spore, oval, highly refractive, easily 

 distinguished, being 2 to 4 /x in diameter, and 4 to 6 ju in length. In badly 

 infected specimens almost every cell in the chyle-stomach of the bee 

 appears to be a mere bag of spores. The ripe spores escape into the colon, 

 are discharged by the bee in flight, and are ingested by other bees when they 



