ISLE OF WIGHT DISEASE IN HIVE BEES — PATHOLOGY. 197 



The Alimentary System. 



As regards the alimentary system, the investigation has but little to add to the 

 observations of former workers. The disordered condition of the alimentary tract 

 has attracted much attention in the search for a clue to the causation of Isle of 

 Wight disease. 



The facts may be briefly outlined. 



In the majority of crawling bees the hind gut and small intestine are distended 

 to the limit of their capacity with accumulated faeces, and the contents of the lower 

 region of the chyle stomach may contain a large admixture of faecal matter. The 

 chyle stomach itself may present a rather wasted appearance, and its contents may 

 be of an unusually deep purple colour. These changes are in all probability merely 

 due to a reduction in the fluid contents. of the organ. 



In the vast majority of crawling bees no lesion is to be found in the alimentary 

 wall either macroscopically or in stained sections. On two occasions only have signs 

 of penetration of the wall by organisms (other than Nosema) been noted. In one 

 case there was an infiltration of the wall near the insertion of the Malpighian tubules 

 by a large filamentous bacillus ; in the other case fungal hyphse had invaded the 

 epithelium of the lower portion of the chyle stomach. Such phenomena are to be 

 regarded merely as terminal infections. 



The flora of the alimentary tract of the normal bee has been carefully investigated 

 and compared with that of bees crawling from the disease. Very little qualitative 

 difference has been found between the two. 



In Isle of Wight disease there is a colonisation of the chyle stomach by the 

 intestinal organisms, and certain organisms, such as coliform bacilli and yeasts, are 

 more frequent and abundant than in healthy bees. Certain streptococci, to be 

 described elsewhere, have also a predilection for the alimentary tract of Isle of 

 Wight bees. 



Malpighian Tubules. 



In a proportion of crawling bees certain of the Malpighian tubules, when mounted 

 in saline, may possess a bright yellow colour due to the presence of large amounts of 

 the excretory pigment. In these coloured areas the excretory granules within the 

 epithelium may be abnormally large and spicular. In fresh preparations the cells' 

 appear to be filled with large bacilli. A similar condition may arise in bees after a 

 period of confinement. 



, Nervous System. 



The examination of the nervous system for pathological changes is as yet very 

 incomplete. The observations of the writer have been mainly restricted to the 

 thoracic ganglia. No changes have been noted in the posterior thoracic ganglionic 



