Kenyon, The Brain of tJu Bee. 137 



seems to follow Viallanes without a question, and deals almost 

 wholly with the ventral system, which he treats anatomically 

 and physiologically. He seems to have added a few new facts 

 to our knowledge of the subject treated, although he leaves 

 very much still to be done. The points at which he seems to 

 have erred or where his treatment is deficient will be noted, 

 when they are closely related to the matter in hand, in subse- 

 quent pages. Here it may be noted that he seems to have ob- 

 tained the beginning of a correct idea of the constitution of the 

 arthropod nervous system based upon the work of Retzius and 

 others employing similar methods ; but, failing completely in 

 his use of the Cajal-Golgi method and obtaining but Htttle better 

 results with methylen blue, he concludes that, since in any one 

 preparation neither of these methods brings out the whole structure 

 they are not to be depended upon, and then passes on to a de- 

 pendence upon a modification of the old method of Weigert 

 and becomes lost in the mass of detail that he so much desired 

 to obtain. 



The results of other writers will be noted in connection 

 with the descriptions of the structures with which their works 

 deal. 



MATERIAL. 



The material used has been almost exclusively the common 

 honey bee {^Apis mellificd), which was at hand in abundance, 

 for which I owe many thanks to Dr. C. F. Hodge. Possibly a 

 thousand or more brains were treated by several of the bichro- 

 mate of silver methods, and of this number scarcely more than 

 fifteen or twenty per cent, were found successfully impregnated. 



METHODS. 



Aside from impregnation with bichromate of silver, the 

 methods that I have employed are various, and among these the 

 one that has given the best results, brought details to light most 

 beautifully, has been one using sulphate of copper and haema- 

 toxylin with brains hardened in from 10 to 20% formol for 

 twenty four hours or longer. Such preparations show the axis- 

 cylinders as purplish-brown fibers within their surrounding 



