4 
G. H. Parker 
Although the connection of ganglionic cells with nerve fibres could 
be veiy clearly demonstrated in preparations made by the raethod just 
de^cribed, it was almost impossible in such material to determine the 
precise location of a ganglionic celi or the exact direction taken by 
its nerve fibre. Since these determinations were necessary in order 
to gain a clear idea of the structure of the ganglia, I attempted to 
devise a process for making sections from material stained in this 
way. Two methods were finally obtained. In the first of these, a 
published account of which has already appeared (cf. Parker, 92), 
the tissues of the ganglion were fixed and the color rendered per- 
manent by means of aqueous corrosive sublimate. Preparatory to 
imbedding in paraffine, the material was dehydrated in methylal 
containing a little corrosive sublimate, instead of in alcohol, then 
transferred to xylol, and finally put into paraffine. The second 
method is essentially like the first except that, in place of methylal 
as a dehydrating reagent, alcohol containing corrosive sublimate 
was used^. As this method has not yet been published, I give 
briefly the .necessary steps in employing it. The ganglia, after being 
freed from the surrounding tissue, were first put into an aqueous so- 
lution of sublimate, then successively into 30^? 50^7 70^» and 95^ 
alcohol, each grade, of course, containing its proper proportion of 
sublimate. The material was allowed io remain in each of these 
fluids about a quarter of an hour. From 95^ alcohol it was trans- 
ferred for an hour to absolute alcohol containing, of course, sub- 
limate, then for another hour to a mixture of one part of this alcohol 
and one part xylol, and finally to pure xylol. The preparation may 
stay indefinitely in this last fluid, from which the transfer to paraffine 
may be made. 
In sections made in either of these ways, the methylen blue 
appeared in the form of a fine precipitate , and the position of ganglion 
cells, as well as the direction of nerve fibres, could be satisfactorily 
ascertained. The method, however, is not so favorable for the study 
of the fibrillar branches into which a nerve fibre subdivides as it is 
for the study of the larger fibres and cells; for the finer fibrillae, 
1 The grades of alcohol required were made by mixing strong alcohol 
containing 8^ corrosive sublimate with water saturated with the same salt; 
thus 30X alcohol consisted of 30 c. c. of strong alcohol containing 8X corrosive 
sublimate and 70 c. c. of water saturated with sublimate. It is advisable to 
prepare the grades of alcohol some time before they are to be used, and to 
filter them after they have been standing a few days. 
