NEUROFIBRILS 473 



other acid solutions which destroy mitochondria. Although it 

 has been suggested by Heidexhaix (Plasma und Zelle, Fischer, 

 Jena, 1911, p. 1110) that the neurosomes may be neurofibrils 

 stained discontinuously, their precise nature is considered at 

 present as vmknown. 



Held's Methylen Blue and Erythrosin Method (Arch. Anat. 

 Phys., Anat. Abth., 1895, p. 399 ; 1897, p. 226). Material may 

 be fixed in alcohol, but preferably either in picro-sulphuric acid, 

 or in van Gehuchten's mixture of alcohol, chloroform and acetic 

 acid, or in 1 per cent, corrosive sublimate in 40 per cent, acetone. 

 Tissues should be carefully imbedded in paraffin and the sections 

 stuck to slides by the water method. They are stained with the 

 aid of gentle heat for one to two minutes in a solution of 1 grm. 

 erythrosin in 150 of distilled water acidulated with 2 drops of 

 glacial acetic acid. After washing with water, the slides are 

 transferred into a mixture of equal parts of Nissl's methylen- 

 blue solution and 5 per cent, acetone, warming until all odour of 

 the latter has disappeared. Differentiation is carried out after 

 cooling by means of a 0-1 per cent, solution of alum until sections 

 are reddish. Rinse in distilled water, dehydrate as rapidly as 

 possible in absolute alcohol, wash in xylol and mount in balsam. 



1006. Other Methods for the Double Staining of Nerve-cells. Rosin 

 {Neurol. Centrbl., xii, 1893, p. 803) fixes the tissues by preference in 

 alcohol or formalin, and imbeds either in paraffin or celloidin. Paraffin 

 sections are stained for five minutes in a mixture of 0-4 grm. of Ehrfich's 

 triacid (powder), 100 e.c. of distilled water, and 7 e.c. of a 0-5 per cent, 

 solution of acid fuchsin. Celloidin sections are stained for one minute 

 in a solution consisting of 4 parts of the above mixture and 1 part of 

 0-5 per cent, acid fuchsin. In both cases the sections are washed in 

 distilled water, differentiated in 1 : 2000 acetic acid, dehydrated with 

 absolute alcohol, cleared in xylol and mounted in balsam. 



Mann (Ztschr. iviss. Mikr., xi, 1894, p. 489) recommends the following 

 for material fixed in one or other of the (watery) solutions men- 

 tioned in § 985. Paraffin sections stuck to slides by the albumen 

 method are treated with Gram's solution of iodine in potassium iodide 

 and washed in water. The still yellow sections are stained for five to 

 ten minutes in 1 per cent, eosin in water, washed once more, and 

 restained for twenty to thirty minutes in a 0-5 per cent, solution of 

 toluidin blue in water. Rinse in water, dehydrate in absolute alcohol, 

 clear in xylol, mount in turpentine-balsam. Instead of toluidin blue 

 4 per cent, of Ehrlich's methjien blue for intra-vitam staining in 



per cent. NaCl can be used. 



B. METHODS FOR CELLS AND FIBRES DEMONSTRATING 



NEUROFIBRILS 



1007. Introduction. Nerve-cells contain, in addition to the 

 granular constituents already dealt with, a so-called achromatic 

 portion apparently consisting of very fine fibrils which can be 

 seen with great difficulty in the unstained state, but can be 



