Brain Preservation 397 



iiig their volume and color to a remarkable degree. All 

 glycerin methods are essentially the same in principle and 

 differ from Giacomini's chiefly in the manner of hardening 

 and manipulation. Giacomini prefers a saturated aqueous 

 solution of zinc chlorid for hardening although potassium 

 bichromate, nitric acid or alcohol will give good results. The 

 pia is removed after an immersion of twenty-four hours in the 

 zinc chlorid solution, the brain remains in the liquid for two 

 or three days longer, until it tends toward the bottom of the 

 vessel, when it should be removed, as a longer stay would 

 cause it to absorb too much water, it is then transferred to 95 

 per cent, alcohol where it may remain indefinitely, ten or 

 twelve days usually being sufficient. The specimen is finally 

 put into pure glycerin or glycerin containing carbolic acid to 

 the amount of one per cent., when it has sunk just below the 

 surface it may be removed and exposed to the air. After a 

 few days when the surface has become Ary, it is varnished 

 with india rubber or better yet with marine glue varnish di- 

 luted with a little alcohol. This completes the process. 



Dissections should be made previous to the glycerin bath. 

 Histological detail is also said to be preserved to a remarkable 

 extent. 



Ivaskowsk}''s" method consists of first washing the fresh 

 specimen in water to remove the blood, it is then placed in the 

 following mixture : 



Water 100 parts. 



95 % Alcohol 20 parts. 



Boracic acid 5 parts. 



Kept in a cool place. 



The pia is removed and the brain then placed in a saturated 

 alcoholic solution of zinc chlorid for five or six days, the 

 bottom of the vessel being covered with cotton. 



Transfer for fifteen or twenty daj^s to a mixture consisting of : 



Glycerin 100 parts. 



Alcohol 20 parts. 



Carbolic acid 5 parts. 



Boracic acid 5 parts. 



Let the specimen dry in the air, protected from dust. 



