50 CHARLES BROOKOVER 



bryology and the adult morphology of the olfactory apparatus 

 in Amia with some comparative work on Lepidosteus and a few 

 teleosts. It has seemed best to include a description of certain 

 sympathetic nerves and ganglia found in the meninges of the 

 forebrain of Amia. 



MATERIAL AND METHODS 



The demands of the various kinds of neurological technique 

 have required the use of a large number of young and adult Amia. 

 At one time time 450 young Amia from 60 mm. to 75 mm. in 

 length were employed for Golgi preparations. In addition to the 

 neurological preparations of young and adult Amia, a great many 

 embryos and young from two days before hatching to 100 mm. 

 in length were sectioned, mounted serially, and stained for cyto- 

 logical results. Most of these sections were stained with Heiden- 

 hain's iron hematoxylin, but others were stained with Delafield's 

 hematoxylin and by Weigert's method. Much of the first 

 material which was available to me for cytological preparations 

 of embryos had been fixed in bichromate-acetic fluid or in forma- 

 lin. Later, when embryos and young were collected they were 

 fixed in Zenker's fluid. 



Some of the neurological methods which gave the best results 

 in my hands will be indicated briefly. The rapid process of 

 Golgi's method (Lee's Vade Mecum, sixth edition, p. 437) gave 

 the best results. Double impregnation was often employed to 

 good advantage. Good results were sometimes procured on 

 adult brains by a preliminary fixation for from five to twelve 

 hours in four per cent formaldehyde neutralized with lithium 

 carbonate or with ammonia. The treatment with neutral forma- 

 lin seemed to favor the impregnation of axones. 



In order to cut serial sections of the Golgi preparations the 

 pieces were imbedded in paraffin melting at about 50° C. Xylol, 

 which dissolves the silver precipitate, was avoided and the clear- 

 ing done in cedar oil. The cedar oil was used repeatedly and is 

 probably all the better for being saturated with silver after use the 

 first time. The cedar oil was warmed over the imbedding oven 



