18 CHARLES P. W. MCCLURE, 



By use of this method, the chroraophilous substance in 

 the nerve cells of Invertebrates, is as that of Verte- 

 brates, alone stained by the raethylen blue; while the 

 remaining structures in the c e 1 1 (nucleoli excepted), a s well 

 as the neuroglia tissue surrounding it, are exclusively 

 stained by the eosin^). 



The staining formula recommended by Mann had to be some- 

 what modified in order to produce the above results, since methylen 

 blues, other than that recommended by Mann (methylen blue 00), 

 were more frequently used ^). 



It was found essential in all cases, where mixtures of eosin and 

 methylen blue were used, that the sections should be stained a deep 

 blue when removed from the same. 



Two mixtures which will produce such a result are as follows: 



1) 1 "/o Methylen blue solution in water 45 ccm 

 1 <'/o Eeosin solution in water ... 35 ccm 



Distilled water 20 ccm 



2) 2 "/o Methylen blue solution in water 35 ccm 

 1 "/o Eosin solution in water ... 40 ccm 



Distilled water 25 ccm 



The length of time which the sections should remain in these 

 staining mixtures, and their subsequent treatment, are the same as 

 recommended by Mann. 



A combination stain, which produces results somewhat similar to 

 the above mentioned combination, is the methylen blue - ery throsin 

 method of Held (16). It is not recommended, however, in place of 

 the former. 



The other combination stain which produced excellent results, 

 was that in which safranin was used in connection with light green. 

 This combination proved particularly valuable, as material fixed in 

 Flemming's solution could be stained by it. This last combination 

 has proved very successful in corroborating the results obtained by 

 the methylen blue-eosin stain; by virtue of the analogous manner, in 

 which by its use, the granules and other elements within 

 the cell, as well as the neuroglia without, are respect- 

 ively differentiated from each other. 



1) By means of this method I have produced similar results on 

 the central and spinal ganglion cells of Vertebrates. 



2) The methylen blue used was that which one ordinarily obtains 

 from Gkübler for staining purposes. 



