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Zbc niMcroecopc anb 1bow to ITlee it. 



By V. A. Latham, F.R.M.S. 



Part XIV. 



Practical Notes on Histology. 

 Special Methods for Examination of the Spinal CaRD, 



Brain, etc. 



THE great difficulties experienced by all investigators of the 

 nervous system have been chiefly fourfold : — 



(a) That of becoming acquainted with the various methods 

 which lie so very scattered amongst the numerous scientific 

 periodicals. 



{^) That of cutting sections of an entire human brain, or 

 large segments of it, of sufficient delicacy for microscopic purposes, 

 and with almost mathematical accuracy. 



(t) That of retaining large masses of hardened nerve tissues 

 in absolutely the same condition as during life, without shrinking 

 or rendering the tissue friable. 



(d) That of demonstrating the dark fibres with such clearness 

 that they can be traced throughout a great part of their course 

 with ease and certainty. All who have worked on the nervous 

 system know how great these difficulties arc, and how much we 

 need some process by which they can be overcome. 



The great obscurity and errors which prevail in regard to the 

 normal and morbid anatomy of the nervous centre is, no doubt, 

 mainly due to these causes. The methods here given are those 

 which have proved of greatest use to me during the examination 

 of these organs, and I sincerely hope they will not be without 

 value to other experimenters. 



General Method. — This investigation is a long and compli- 

 cated one, the tissues having to pass through the following stages 

 in the order given : — 



I., Hardening ; H., Cutting ; HI., Staining ; IV., Mounting ; 

 each stage claiming its own special process. 



I. Hardening the Tissues.-— Cut into small pieces, place them 

 in methylated si)irit, and let them stay for about two days 



