No. 402.] THE NEURONE .THEORY. 469 
system together: Ganglion cells are those cells that produce 
what is transmitted by the fibrillar substance, namely, nervous 
impulses. : 
So far as I am aware, Apathy has never placed upon record 
the observations that justify these distinctions, and, as criticism 
and acceptance of his unsupported statements are equally pre- 
mature, it seems to me that, till facts are presented, this side 
of his work must be passed over. If this is done, the character 
of the fibrillar substance is the only feature of Apáthy's work 
that requires present consideration. The distribution of this* 
substance is for the most part within neurones. Hence Apá- 
thy’s discoveries have to do mostly with the internal anatomy 
of the neurone, and from this standpoint they afford no ground 
for attacking the neurone theory. In one respect, however, 
they bear in an important way on this theory, namely, in the 
structure they indicate for the neuropile. Is the neuropile a 
continuous network made up of the anastomosés of neurofibrils, 
as claimed by Apathy, or does it lack this continuity in that it 
is composed of systems of branches derived each from a sepa- 
rate neurone and related only through contact, as implied by 
the neurone theory ? 
Apáthy's figures and statements favor in an unqualified way 
the idea of continuity, but the solution of this problem, one of 
the most difficult in modern histology, is to be accomplished 
only by the aid of many hands. It is, therefore, gratifying to 
find that Bethe has devoted no small amount of time to a criti- 
cal study of Apáthy's methods and results. Bethe has con- 
firmed many important statements made by Apáthy, but he 
has been unable to find reasons for accepting Apáthy's distinc- 
tion of ganglion and nerve cells, and he has shown that Apá- 
thy's generalization of motor fibres, being characterized by one 
coarse fibril, and sensory fibres by many small ones, does not 
hold true for the arthropods. He has, however, confirmed the 
principal statements of Apáthy as to the presence of neurofibrils 
in nerve fibres and in cells ; and, on the important question of 
the nature of the neuropile, Bethe agrees in his conclusions 
with Apáthy in stating that it is a continuous network. When, 
however, the facts for this conclusion are sought for in the 
