No. 402.] THE NEURONE THEORY. 467 
cases seem to be relatively rare. So far as their bearing on 
the neurone theory is concerned, I agree with Barker that they 
form no greater objection to the general theory than the occur- 
rence of Siamese twins does to the general idea that the human 
species is represented by separate individuals. This form of 
objection has certainly shown itself to be trivial. 
A much more serious obstacle comes from the work associ- 
ated with the name of Apáthy. This investigator has devel- 
oped methods which in point of perfection exceed the Golgi 
V m 
Fic. 4. — Posterior view of a transverse section of the ventral nerve chain of a leech (modified 
from Apáthy). The median plane of the leech is represented by D (dorsal), V (ventral). 
the left side (Z), t p g y: 
a sensory being rej lin solid black, and a motor one dotted. On the right 
' Side (R) the nervous elements are represented according to Apathy. The neurofibrils 
begin in or betw he i ithelial cells (E), fr hich they pass centrally 
5 y ep (4), wW. 
into sensory ganglion cells (S) or motor ganglion cells (Af). From the latter, coarse 
neurofibrils pass peripherally to muscles. The neurofibrils are produced by nerve cells, 
a nucleus of one of which is shown at JV. 
and the methylen-blue methods as much as these surpassed the 
ones before them. Apdthy’s methods do not outline neurones ; 
they differentiate the transmitting substance within the neu- 
rone. Instead of a coarse nerve fibre or ganglion cell colored 
homogeneously, one finds a clearly differentiated system of 
delicate fibrils that constitute collectively the transmitting 
apparatus of the nervous organs. The peculiarities of Apá- 
thy's methods can be easily appreciated by inspecting the 
accompanying diagram (Fig. 4), taken from the nervous system 
