Hara, Sheaths of the Peripheral Nerves. 153 
shown in Fig. 2, 6, while in some cases larger spaces of the 
network are noticed at the small end of the funnel (Fig. 3) 
while the basal portion of the funnel has much finer meshes. 
Wyyn ('00), who studied the medullary sheath by using 
the PaL-WEIGERT technique, states that each cone is composed 
of six segments, placed at regular distances apart, and converg- 
ing from the primitive sheath to the axis cylinder. The pres- 
ent writer has examined a large number of preparations 
stained with Pat-WEIGERT technique, but fails to confirm this 
result, although, in some cases, there are six dots placed at 
regular distances (Fig. 1,a) and located in some cases along the 
inner margin of the primitive sheath and sometimes closely sur- 
rounding the axis cylinder. A careful examination, however, 
reveals that in most cases more than six dots are to be seen, 
and furthermore, each dot is not a single dot but composed of 
several irregular lines and minute dots, thus giving a structure 
such as is to be seen in my preparations. According to 
Wiassak’s (00) investigation, the PaL-WEIGERT technique 
stains only the substance known as cerebrin, which is a con- 
stituent of the myelin, but not of the neurokeratin. If this 
statement of WLassak is true, the Pat-WEIGERT technique 
shows a distribution of the cerebrin in the medullary sheath, 
but not the distribution of the neurokeratin. The six rods de- 
scribed by Wynn, therefore, may prove that the cerebrin in the 
medullary sheath is distributed in a special relation to the 
cones ; in other words, the cerebrin and neurokeratin are closely 
interdependent in their distribution. Wyww arrived, however, 
at the conclusion that the substance which forms the cones is 
neither a fatty body, nor neurokeratin, but a nucleoproteid. 
The statement given by Wynn, that the six dots given in the 
medullary sheath brought out by Pat-WeEIGErT technique, are 
not the neurokeratin, seems very probable, for by comparing 
sections by the Pat-WEIGERT method with mine for neuro- 
keratin, the dots of the former are seen to be of a size compara- 
ble with the spaces formed by the neurokeratin net in my slides 
and thus the two preparations give complementary pictures 
(Fig. 5). Passing by the contradictory statements of Wynn 
