192 HELEN L. M. PIXBLL-GOODEIOH. 



especially to a weak colony, and li^ave ultimately to be turned 

 out of the hive by its younger and more vigorous members. 

 Bees having so few ways of showing their symptoms, it 

 will be readily understood that there is much diiSculty in 

 differentiating disease from senescence at sight. If a bee is 

 ill or very old it will first be unable to fly and later hardly 

 able to crawl. Many "bee-experts" diagnose a crawling 

 bee to be suffering from " Isle of Wight " ^ disease if its 

 rectum is distended with an accumulation of undigested 

 pollen, wax, etc., which can be readily squeezed out by slight 

 pressure. It must be remembered, however, that, since bees 

 normally defsecate on the wing, there will tend to be a 

 collection of such undigested matter in any bees unable to fly. 

 Before proceeding further ifc will be well to explain briefly 

 how far the investigation of the common diseases of adult 

 bees has progressed in this country.' Among diseases which 

 can be diagnosed microscopically or bacteriologically are : 



(1) Microsporidiosis or Nose ma disease due to the 

 protozoan parasite Nosema apis, Zander, which has been 

 described by Fantham and Porter (7). Much has been written 

 on this disease (7a, 20), which is not at present at all common in 

 England. No doubt the activities of the Board of Agriculture 

 since 1906 have helped to reduce the frequency of its 

 occurrence. 



(2) A form of dysentery or inability to retain fseces 

 appears to be due to a small oval yeast — possibly of more than 

 one species. The contents of the colon in affected bees are 

 often watery, and always show enormous numbers of actively 

 budding yeasts which are also present in the ventriculus. 

 These organisms, which stain readilyby the Gram or Claudius 

 method, have never been found in the walls of the alimentary 

 canal nor in other tissues. They are readily stained and 

 therefore presumably killed by methylene blue, so that no 

 doubt this and other mild antiseptics help to reduce their 

 numbers. In these disorders, therefore, spraying and raedi- 

 cated feeding are likely to have some beneficial effect. 



' See footnote to p. 193. 



