SECTION TWO 



E. Silver nitrate, io% aqueous 



F. Solution E . . . . . . 50 ml. 



Pyridine, pure . . . . • • 3'75 mi- 

 Distilled water . . . . . . 200 ml. 



G. Strong ammonia solution, spec. 



gravity o-88 . . . . . . 7 ml. 



Distilled water . . . . . . 18 ml. 



H. Silver diaminohydroxide solution 



Place I ml. of solution G in a scrupulously clean 

 flask whith has been washed out with three lots of 

 distilled water. Add 7-8 ml. of solution E to the 

 I ml. of dilute ammonia solution in the flask. Shake 

 well. Cautiously add drop by drop more silver 

 nitrate, shaking the flask between each addition, until 

 the precipitate redissolves except for a faint turbidity 

 which must be allowed to remain if the preparation 

 is to be effective. A total of 9-10 ml. (including the 

 the 7 or 8 ml. placed in the flask in the first place) 

 of the 10% silver nitrate will be required. 



I. Solution H 

 Pyridine . . 



J. Neutral formalin, 2% 

 Absolute alcohol 



i.e. Formaldehyde, 40% solu- 

 tion, neutral 

 Distilled water, neutral 



K. Gold chloride (brown or yellow), 

 0-2% aqueous 



L. Sodium thiosulphate, 5% aqueous 



M. Eosin or erythrosin, 1% in tap 

 water 





'echnique: 



1. Fix small pieces of fresh brain tissue in 10% neutral formalin 

 for one week. 



2. Wash in tap water. 



3. Dehydrate through the usual graded alcohols. 



4. Clear in xylol 



415 



