PREFACE. 



Bees, like many other members of the animal kingdom, are 

 known to suffer from diseases. Simultaneously with the good work 

 that has been done during the last half century toward the deter- 

 mination of the causes of the various diseases of man and animals, 

 there has been some work done on the causes of bee diseases. This 

 work has caused considerable literature to be written on the subject. 

 Although this literature contains much that is valuable, it abounds 

 in statements that are erroneous and in conclusions that seem 

 unjustifiable. Many of the inaccurate statements and conclusions 

 have been frequently copied in the past and they are stUl too often 

 copied into the current literature on bee diseases. The bee keeper, 

 therefore, in reading is often at a loss to know what is true and 

 what is untrue; what is actually known and what is not knowTi. 



For the purpose of aiding the bee keepers with this literature, 

 we have reviewed here portions ot several original papers dealing 

 with the causes of bee diseases. It is hoped that this bulletin may 

 serve as a means whereby the bee keeper may solve for himself 

 some of the apparent mysteries found in beekeeping literature. 



In selecting the papers for review, for the most part, those were 

 chosen which were written by men who had worked more or less 

 on the causes of bee diseases. The reviews that have been made 

 contain the more important beliefs concerning the causes of tliese 

 diseases that were entertained by the authors of the different papers 

 at the time they ^vTote. The classification of the diseases of bees as 

 understood by these different men is also frequently included. The 

 original papers naturally contain much that has not been mentioned 

 in these brief reviews, and therefore the reader is urged, if oppor- 

 tunity permits, to read the papers cited in this bulletin rather than 

 the reviews. It is probable that the papers here considered might 

 with profit have been more completely reviewed and that other papers 

 might mth profit have been considered, but if either had been done 

 it is probable that the length of the bulletin would have defeated its 

 object. 



It is hoped that the readers of bee-disease literature will learn, so 

 far as possible, to judge correctly an article that discusses in any 

 way the causes of bee diseases. To do this, one should first of aU 

 learn who are actually doing work on the causes of these diseases. 



7 



