2710 Journal of Applied Microscopy 



agents. Sections were stained in Mayer's haemalum. which gives a fine nuclear 

 differentiation and stains also the mucous glands. Eosin in aqueous and in 

 alcoholic solutions, with and without a trace of acetic acid, was used as a 

 plasma stain. The acetic-eosin was found to demonstrate in some instances 

 the nerve fibers and finest nerve fibrilla; when employed as follows : The sec- 

 tions after staining in haemalum were flooded with distilled water, to which 2 

 drops of acetic acid had been added, and after a few minutes exposure, the 

 water is poured off and a few drops of an aqueous solution of eosin was added. 

 A precipitate is formed which is washed off after a few moments, and the slide 

 is then soaked in distilled water, dehydrated quickly in absolute alcohol and 

 mounted in balsam. The peripheral nervous system was demonstrated in total 

 preparations from underfed animals in whose nerves a granula is formed which 

 blackens readily in osmic acid. The narcotized mussels are fixed in Flemming's 

 stronger mixture for several days, the shell removed, the soft parts washed in 

 water, and passed through alcohol grades in bright sunlight. In the course of a 

 few days this brings about an intense blackening of the nerves, which can then 

 be followed readily in material cleared in zylol or benzole. The course of the 

 more centrally placed nerves may be followed by dissection of the cleared mate- 

 rial. The course of the digestion tract was demonstrated upon animals in which 

 the sexual glands were not developed by feeding them upon finely ground india 

 ink, which quickly fills the intestine and begins to invade the liver. The animals 

 are narcotized before this invasion proceeds very far, are fixed in nitric acid- 

 alcohol or picro-nitric mixture. When cleared in zylol the course of the diges- 

 tive tract is plainly demonstrated. c. a. k. 



None of the methods usually recom- 

 Tower, W. L. The Origin and Development . i- ii 



oftheWingsoftheColeoptera. Zool. Jahrb. mended for msect tissues gave reliable 

 Abth. f. Anat. u. Ont. 17: 517-572, Taf. results in all cases. Perenyi's fluid 

 14-20, and 8 figs, in text, 19:3. , - . u uv ^ 



used hot or cold, sublimate, picric or 



chromic acid mixtures were unsatisfactory. Hermann's and Flemming's fluids 

 gave excellent results with small pieces or young larva-, but were not adapted to 

 old larvae or large pupae. The following sublimate-acetic mixtures were devised 

 and are stated to give results exactly like those given by Hermann's and Flem- 

 ming's fluids : 



No. I No. 2 No. 3 



Saturated solution of corrosive sublimate in 35 

 per cent, alcohol . . . . - 



Glacial acetic acid . - - - - 



Nitric acid c. p. - 



Platinic chloride 2 per cent, in distilled water — — 30 



Number 1 is used for large larva; or pupae, heated to 80° C. in a closed flask 

 and poured suddenly over the specimens and allowed to act for 2 to 5 minutes. 

 It is then replaced with No. 2 and the temperature is maintained at 80 to 40° C. 

 for several hours. After removal from No. 1 the insect should be cut in several 

 pieces with a knife. Small larvae and pupae should be fixed in No. 2. Number 3 

 was the most generally useful reagent, giving excellent results when used either 

 warm or cold, but it should be applied only to small pieces of tissue. After 



