396 CENTRAL NERVOUS SYSTEM. 



in O'l per cent, solution of rnethylen blue, differentiated in alcohol, cleared 

 in origanum oil, and mounted in colophonium. Nuclei and axis-cylinders, 

 red. This stain is said to prove that the nuclei of the ganglion-cells of the 

 rabbit contain only one true nucleolus, instead of two or more, as has been 

 hitherto believed. 



752. For a plasma-stain REHM (1. c.) gives a method modified from 

 NISSL. Sections of alcohol-hardened material are stained for half a minute 

 to a minute in a hot O'l per cent, solution of methylen blue, washed in 

 96 per cent, alcohol till no more colour comes away, cleared with origanum 

 oil, and mounted in balsam or benzin-colophonium. Nerve-cells, dark blue ; 

 connective-tissue cells lighter, and greenish. 



753. To obtain a sharper distinction between nerve-cells and connective- 

 tissue cells, REHM stains as before in the hot methylen-blue solution for 

 not more than half a minute, and washes out as before with 96 per cent, 

 alcohol. The sections are then stained for fifteen to thirty minutes in a O'l 

 per cent, solution of fuchsin in 96 per cent, alcohol, washed out for a minute, 

 until no more red colour comes away, in alcohol, cleared in clove oil, and 

 mounted. Nerve-cells blue-red, their nuclei being unstained ; nuclei of 

 connective tissue and of vessels, brilliant red. 



This distinction is not obtained in embryonic tissues. 



Nuclei of connective tissue and vessels may also be brought out by 

 staining for a few minutes in 1 per cent, aqueous solution of eosin, fol- 

 lowed by a few minutes in warm O'l per cent, aqueous solution of dahlia, 

 dehydration, and mounting (the nuclei blue, all else red). Or 1 per cent, 

 aqueous solution of nigrosin may be taken instead of the eosin, and O'l per 

 cent, alcoholic solution of fuchsin (half an hour) instead of the dahlia 

 (nuclei red, all else grey-blue). 



754. Haematoxylin may be used as a general stain. Bevan 

 Lewis recommends the formula of Kleinenberg, or a formula 

 that he attributes to Minot, which is essentially the same as 

 Bohmer's. BERNHEIMER'S formula, which is quoted in regard 

 to the retina, 683, is practically the same thing. 



MALLORY'S Phospho-molybdic Acid Haematoxylin Stain has 

 been given in 195. 



SCHIEFFERDECKER and YoBis find that celloidin sections of 

 material hardened in Miiller stain well in it. 



755. HAUG (Zeit.f. wiss. Mik., vii, 2, 1890, p. 153) gives the following 

 modification of WEIGEBT'S process, as being more convenient to carry out, 

 and serving to demonstrate all the elements of spinal cord with equal clear- 

 ness. Small segments of fresh cord are put into saturated aqueous solution 

 of neutral acetate of copper. After two days (or, for large specimens, longer) 

 they are put for a day or a day and a half into a 5 per cent, or even saturated 

 solution of bichromate of potash. They are next rinsed with water and put 

 for thirty-six to forty-eight hours into 70 per cent, alcohol in the dark. 

 They are then treated for the same time with absolute alcohol, also in the 



