METHOD XVI. 



GIACOMINI'S METHOD (MODIFIED). 



A method for making ''dry preparations" of the central 

 nervous system for museum specimens. 



REAGENTS REQUIRED. 



A. Saturated zinc chloride solution. — 



Zinc chloride, 2,000 g. 

 Water, 600 cc. 

 The solution is of a sirupy consistency and of high specific gravity. 



B. Commercial alcohol (95 per cent.), about 5 liters. 



C. Oil of turpentine, about 3 liters. 



D. Ordinary '' soft" paraffin, about 2 kilos. 



E. Oil Varnish or, preferably, shellac varnish. 

 Shellac varnish is a thick solution of shellac in strong alcohol. 



The reagents are called for in quantities, sufficient for the 

 preparation of the adult human encephalon. Smaller specimens 

 will require correspondingly smaller quantities. 



PROCEDURE. 



I. Place the freshly removed brain (with spinal cord attached, 

 if desired) in 2—3 times its volume of the saturated zinc 

 chloride (A). 



If possible, before removing the brain, inject about 600 cc. 

 of the zinc chloride into it by way of the internal carotid artery. 

 Previous injection is especially necessary, if there is reason to 

 believe that the tissue has become soft through having been left 

 too long after the death of the subject. 



The brain will float in the fluid during the first 2 or 3 days, 

 and must therefore be turned frequently so that the fluid may 

 penetrate equally from all sides. To further hasten the penetra- 

 tion, keep the top side of the specimen covered with absorbent 

 cotton wet in the fluid. Enough fluid must be used to well cover 



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