

III. 



NOTE ON THE PRESERVATION OF ENCEPHALA 

 BY THE ZINC CHLORIDE. 



It has long been known that zinc chloride may be used in 

 conjunction with spirit for the preservation of encephala. Gratiolet 

 in a note at p. 1 1 of his famous ' Memoire sur les plis cerebraux 

 de l'Homme et des Primates/ 1854, informs us that a certain 

 Parisian modeller, by name Stahl, was in the habit of hardening 

 brains for modelling, by placing them whilst fresh, and with the 

 membranes adherent, for two or three days in a solution of zinc 

 chloride marking 25 on the areometer of Gay-Lussac. Gratiolet, 

 however, does not say that he himself treated brains in this 

 fashion for his own purpose ; if he had so treated them he would 

 have discovered that for purposes of manipulation it % is necessary to 

 subject the brain thus acted upon to an immersion in alcohol. 

 This Professor von Bischoff of Munich pointed out in his Memoir 

 on f Die Grosshirnwindungen des Menschen' (' Abhandlungen der k. 

 bayer. Akad. der Wiss/ CI. ii. Bd. x. Abtheil. ii. 1868, p. 401, or 

 ' S. A.' pp. 11, 12), stating at the same time that having employed 

 the solution of zinc chloride for twenty-four years for the preserva- 

 tion of subjects for dissection he had observed that the brains of 

 subjects thus injected, and brains simply put into this solution, 

 presented the following advantages for purposes of study. They 

 become more plastic and tough, less liable to chapping and break- 

 ing away in flakes, than brains simply treated with alcohol ; but 

 they do require some subsequent supplementary immersion in 

 alcohol of moderate strength to prevent the acid chloride, which at 

 first coagulates, from softening the albuminous substances of the 

 organ. A second, and this not an inconsiderable advantage, is 

 attained by their allowing the pia mater to be stripped away with 



