NEUROLOC4ICAL METHODS. 379 



the carotid if he wished to limit the hardening to the en- 

 cephalon, or through the aorta if he desired to fix the spinal 

 cord. 



DE QUEEVAIN (Vircliou-'ff Archiv, cxxxiii, 1893, p. 489 ; 

 Zeit. f. ict'.ss. J/'i'/t., x,, 4, 1893, p. 507) proceeds in a similar 

 manner, injecting solution of Miiller warmed to bod} r heat. 

 For dogs 300 to 400 c.c. are required, for cats one third to 

 one half that quantity. After injection the whole organ is 

 put into solution of Miiller for some weeks. 



(Further details in last edition.) 



MANX (Zeit. /. wist. Mik., xi, 4, 1894, p. 482) injects 

 through the aorta. Before throwing in the fixing liquid, he 

 injects for about twenty seconds physiological salt solution 

 warmed to 39 C. This washes out the capillaries, and 

 prevents the blood from coagulating there. The fixing solu- 

 tion employed by him consists of saturated solution of corro- 

 sive sublimate, warmed to 39 C. After five minutes of injec- 

 tion the brain ought to be fixed throughout. It is removed 

 and put for twelve hours into the same sublimate solution, 

 after which it is either put for permanent preservation into O'l 

 per cent, solution of sublimate, or is at once passed through 

 alcohol for imbedding in paraffin. 



See also 754. 



STRONG (New York Acad. of Sci., January 13th, 1896 ; 

 Anat. An::., xi, 21, 1896, p. 655) advises injecting formalin 

 diluted with an equal volume of water, or (for the GOLGI 

 method) with an equal volume of 10 per cent, solution of 

 potassium bichromate ; which seems to me very heroic (see 

 104). 



Hardening. 



682. Hardening by the Freezing Method. The ether freezing 

 method is to be preferred. The sections should be floated on to water, 

 treated for a ruinute on the slide with 0'25 per cent, osmic acid solution, 

 and stained or otherwise treated as desired. 



For a detailed description of these manipulations see BEVAX LEWIS'S The 

 Human Brain. 



GOODALL'S Eapid Method for preparing Spinal Cord (Brit. Med. Journ., 

 May, 1893, p. 947 ; Journ. Roy. Mic. Soc., 1893, p. 405). Cut sections of 

 fresh tissue with a freezing microtome ; float them on to water, and as soon 

 as possible drain them and float them on to pyridin. After a quarter of an 



