BY THE ZINC CHLORIDE. 55 



necessary. Brains, however, like other organs, vary very much in 

 their consistence and power of taking on consistence after death, 

 and the amount of uncertainty which attaches to this latter mode 

 of preserving brains may perhaps be explained otherwise. Thirdly, 

 I have observed in adult human brains, treated with Burnett's 

 solution of zinc chloride, that the larger arteries will, if not re- 

 moved sufficiently early, recoil or retract themselves as arteries in 

 a living body will do when cut away from their peripheral ramifi- 

 cations, and so come to imbed themselves in the substance of the 

 convolutions, and thereby channel and disfigure them. In this 

 matter of the expediency of not delaying the removal of the 

 membranes, the nitric acid method coincides with the zinc chloride. 

 (For this, as regards the former method, see Dr. Bevan Lewis, 

 cit. Dr. J. Crichton Browne, on General Paralysis of the Insane, 

 'West Riding Lunatic Asylum Medical Reports,' vol. vi. 1876, 

 p. 203.) 



In conclusion, I may draw attention to the fact that Dtivernoy 

 in his Memoir on the Nervous System of the Lamellibranchiata, 

 published with exquisite and accurate illustrations in the f Me- 

 moires de l'lnstitut,' 1854, p. 8, tells us that he used zinc chloride 

 for his dissections. 



The specific gravity of Burnett's solution of zinc chloride is 

 about 1*343, and it may be used undiluted for the purposes in 

 question. The above method of preserving the brain, which we 

 have for some years carried out in the Oxford Museum, agrees 

 in its essential features with the first stage of the process recently 

 described by Dr. Carlo Giacomini in a communication made to 

 the Royal Academy of Medicine of Turin. (See Abstract in 

 Report on recent memoirs on the Anatomy of the Brain in ' Journal 

 of Anatomy and Physiology,' Jan. 1879.) 



