64 
BULLETIN OF THE LABORATORIES 
have made upon the cerebellum it may be proper to enumerate some 
of the results of the late investigations of Golgi (Sulla fina anatomia 
degli organ! central! del sistema nervosa, 1886,) of Ramon y Cajal 
(Revista trimestrial de Histologia normal y patologica, Aug., 1888,) 
and, more recently, of Prof. Koelliker, which seem not to have attract- 
ed the attention they deserve in America. 
It remains to be seen how far the metallic impregnation upon 
which Golgi’s method rests, develops normal structures and how far it 
may be relied on to differentiate solely nervous tissues. Really suc- 
cessful hsematoxylin and cochineal stains will reveal most of the de- 
tails, though less conspicuously, and are not open to the objection that 
the stain may be a more or less mechanical precipitate rather than a 
truly selective stain. 
Golgi’s chief discoveries are the following: The Purkinje’s cells 
have two sorts of processes, the peripheral protoplasmic processes, 
which subdivide almost indefinitely, but do not terminate in nerve 
fibres or a nervous reticulum, and a median axis- cylinder process, which 
is occasionally furnished with lateral branches. 
In spite of the numerous subdivisions of the process, anastamosis 
is said never to take place between different cells. The Purkinje’s 
cells lie between the outer or molecular zone and the deeper or granu- 
lar zone. 
In the former layer Golgi recognized small cells of variable form 
with both branching and axis-cylinder processes, which latter also sub- 
divide but do not reveal their ultimate course. 
In the granular layer Golgi found small nerve cells with a delicate 
axis-cylinder process and short and few protoplasmic processes 
extending to granular aggregates. There are also, still more rarely, 
larger cells of a fusiform shape and very numerous branches of the 
axis-cylinder. 
Golgi claims that the medullated nerve fibers in the white layer, 
and especially in the granular and molecular layers, anastamose largely. 
This latter fact is not substantiated by Cajal, who, moreover, consid- 
ers the axis-cylinder of the granular cells, and of the small cells of the 
molecular layer as well as those of the larger cells of the granular layer 
as non-medullated. 
Koelhker summarizes his own observations in the following aphor- 
isms : 
“All free, non-medullated processes of nerve-fibres are, in my 
