310 RETINA, INNER EAR, NEKVES. 



instead of pure hsematoxylin. One part of commercial extract of logwood is 

 dissolved in 90 parts of water and 10 of alcohol. To the filtered solution is 

 added 8 drops of concentrated solution of lithium carbonate for each 100 c.c. 

 Sections require from eighteen to twenty-four hours in the stain at the 

 normal temperature. 



The results obtained by Weigert's method are most splendid. 

 The blue-black nerves stand out with admirable boldness on 

 a golden ground. The method is applicable to the study of 

 peripheral nerves as well as to nerve-centres ; and is likely to 

 be of great utility in vertebrate embryology. 



Nerve-tissue is not the only tissue stained by the process, 

 which can be usefully applied to lymphatic glands and to 

 skin (see SCHIEFFERDECKER, in Anat. Anz., ii, 1887,, p. 680). 



651. Modifications of WEIGERT'S Method. MAXFLESCH (Zeit. 

 f. wiss. Mik.j 1884, p. 564). Sections, made either by the 

 celloidin process or otherwise, are put for a few minutes or 

 longer into 0*5 per cent, chromic acid solution; they are then 

 rinsed in water, and brought into the stain, where they take 

 on a sufficient colouration much more rapidly than the tissues 

 will if stained in the mass. Decolouration is done in the 

 usual way. No stove is required in this process, and either 

 brown or green material may be used. Flesch finds (1. c., 

 1886, p. 51) that this method is to be preferred to Weigert's 

 copper method in all cases in which it is important to produce 

 differential staining in nerve-cells, and especially in the study 

 of peripheral ganglia, and also for producing differential 

 staining of the medulla of central and peripheral nerves, 

 whilst the copper process is mcsfc certainly superior for the 

 demonstration of fine nerve-fibres. 



BENDA (Verhandl. Physiol. Ges., Berlin, 1885-86, Nos. 12 

 13, 14 ; Zeit.f. wiss. Mik., iii, 3, 1886, p. 410 ; Arch. f. Anat. 

 u. Phys., 1886, p. 562). The tissues are to be fixed and 

 hardened for at least three days in saturated solution of picric 

 acid, washed out for several days in water, hardened in 

 alcohol, imbedded in paraffin, and sections made. The sec- 

 tions are mordanted by treating them, for a few minutes or 

 hours with a salt of iron, for which purpose concentrated 

 solution of ammonio-sulphate of iron is recommended. After 

 being well washed in several changes of water, they are 

 stained for about ten minutes in 1 per cent, aqueous solution 

 of haematoxylin, then decoloured by treatment for about five 



