OcTOBER 30, 1902] 
NATURE 
665 
observers, Howell and Huber, who had used both histological 
and experimental methods, had arrived at the conclusion that 
the axis cylinder, the essential portion of a nerve-fibre, had an 
exclusively central origin; they admitted that the peripheral 
tissues in which it was embedded were active in preparing and 
generating a nutritive scaffolding for it. With Dr. Mott he 
had come to experimental results which, so far as they at pre- 
sent went, confirmed those by Howell and Huber. One experi- 
ment they had performed was to divide a large nerve and 
suture the ends together. After a sufficient length of time had 
passed, restoration of function occurred, and this was taken as a 
sign that regeneration had successfully ensued. Then they ex- 
posed the nerve-trunk anew. The union of the two ends was 
then found to have been accomplished, and on testing the nerve 
it was found to be excitable by faradisation when the stimulus was 
applied either below or above the point of reunion of the divided 
trunk. A piece of the nerve-trunk was then excised some little 
distance below the point of reunion ; on microscopical examin- 
ation of this, new nerve-fibres were discovered within it. Subse- 
quent to this second operation, the wound was closed up and the 
animal was finally sacrificed ten days later. When the animal 
was finally then examined, the nerve both above and below the 
second section was once more tested for response to electric 
stimulation. The peripheral piece was then found to have 
become once more inexcitable. Degeneration had also set in 
within the fibres of the peripheral piece of the nerve-trunk. 
Prof. Halliburton urged that this showed that the degenerative 
process which followed the direction of growth had occurred 
in a peripheral direction only and had not started at the peri- 
phery. Observations were also mentioned indicating that 
normal functional activity exercised an important influence on 
the speed and perfection of the process of nerve repair. 
Paralysis was induced in the arm of the monkey by section 
of a number of the cervico-brachial afferent spinal roots. By 
this device, the motor cells of the cord in that region, namely, 
the cells whence originate the motor nerve-fibres of the limb, 
are cut off from the influence of all impulses coming to them 
reflexly from the sensory nerves of the limb itself. A large 
nerve-trunk in the arm is then divided and the corresponding 
nerve-trunk of the opposite non-paralysed limb is likewise cut, 
the latter as a control experiment. Union of the ends of the 
divided nerves occurred on both sides, but on the side on which 
the afferent roots had been cut the union was much slower and 
less perfect, as shown both by histological and by electrical 
examination of the nerve. 
Prof. Schafer communicated the results of a series of experi- 
ments executed with the object of analysing further the 
mechanism connecting the muscular apparatus with the 
centres for willed movement having their seat within the 
brain. He compared the relative effects of transection of the 
pyramidal tracts and of the ventral columns of the spinal cord. 
The observations had been made on monkeys. Section of the 
ventral columns of the spinal cord produced paralysis of volun- 
tary movement in the parts of the body lying behind the seg- 
mental level of the lesion. The descending fibres of the 
ventral columns of the cord were in the main derived from the 
cells of the nucleus of Deiters in the bulb, a group of fibres that 
were, on the other hand, related to the impulses entering the 
brain from the labyrinth organ, namely, the semicircular canals 
and the otolith organ. It had been proved by Ewald and 
others that the destruction of the labyrinth organ entailed 
diminution and impairment of the ‘‘tonus” of the voluntary 
muscles of the body. Prof. Schafer proposed to account for the 
paralysis ensuent upon transection of the ventral spinal columns 
by the removal of the bracing influence of Deiter’s nucleus 
from the ventral horn cells of the spinal cord, the tonus of 
muscles being certainly primarily a tonus of the ventral horn 
cells of the cord. The paralysis produced by section of the 
ventral columns of the cord would on this explanation be com- 
parable with that described by Sherrington and Mott in the 
monkey consequent on section of the afferent roots, which 
seems to take effect by producing loss of tonus in the motor 
nerve-cells, 
A paper on some new features in the intimate structure of 
the human cerebral cortex was read by Dr. John Turner. His 
specimens showed (1) a beaded network enveloping the 
pyramidal cells of the cortex and their dendrites ; (2) an inter- 
cellular plexus of nerve-fibrils not previously demonstrated to 
exist. The preparations demonstrating these points had been 
made by placing pieces of the brain tissue directly on removal 
NO. 1722, VOL. 66] 
from the body, and without previous hardening or fixing, into 
a staining solution containing methylene blu? and hydrogen 
peroxide. From this mixture, after a sufficient time had elapsed, 
the tissue was transferred to a solution of molybdate of am- 
monia. The tissue was then after this fixation dehydrated, 
embedded in paraffin and cut into sections. The bzaded net- 
work is anetwork, not of neuroglial fibres, but of processes of 
true nerve-cells. This network loosely invests the pyramidal 
cells and their dendrites. The network is made up of the finer 
ramifications of stouter fibres which can be traced from certain 
pyriform dark cells in the cerebral cortex ; these cells are 
generally small, and no signs of any network can be seen around 
them. There seem, in fact, in the cortex of the cerebrum to be 
at least two systems of nerve-cells present, the pyramidal variety, 
which are pale under the method of examination here employed, 
and the smaller darkly stained pyriform nerve-cells.’ These 
latter possess branches which ramify and form by a fusion a 
network enveloping the pyramidal cells. Since the network is 
a true network formed by actual anastomosis, the system of dark 
cells constitutes a contznuum. Dr. Turner urged that in all 
probability collaterals arising from the axons of the pyramidal 
cells also joined on to the network. If that were so, all the 
nerve-cells of the cortex would be practically in organic con- 
tinuity. He suggested that the differences observed in staining, 
shape, arrangement, &c., of the two varieties of cells indicated 
a differencein function. There was good ground for associating 
the pyramidal cells with motor functions; he was therefore 
inclined to ascribe to the dark pyriform cells sensory functions. 
They were in all likelihood, he urged, the bearers and distri- 
butors of afferent impulses. This method might therefore afford 
a means of showing where ingoing currents ended and where 
outgoing currents started. On this view, however, the impulses 
must flow in a centrifugal direction in the dendrites of the dark 
cells andj in a centripetal direction in the axons of those cells ; 
this was against the views generally in acceptance which regard 
the axon as always a cellulifugal conductor and the dendrites as 
always conducting in a direction toward the perikaryon. 
Prof. Schafer corroborated the description of the microscopi- 
cal structures described and discovered by Dr. Turner. He 
suggested, however, that the course of conduction was not 
cellulifugal in the dendrites of the dark cells. He argued that 
it was more probable that the nervous pericellular network took 
upimpulses brought by the afferent fibres coming to the cortex 
in such large numbers from the optic thalamus ; that these im- 
pulses in part were carried through the pyramid cells and in 
part through the dendrites of the dark cells to the perikarya and 
axons of these latter. 
Dr. Page May communicated a paper upon the movements 
and innervation of the stomach. His investigation had been an 
experimental one, and the animals employed had been cats, 
dogs and monkeys. A short time after taking food, movements 
of a rhythmic character arise in the muscle of the wall of the 
organ. These movements are waves of contraction, each of 
which commences near the cesophageal end of the stomach. The 
waves succeed each other at a rate of about three times per 
minute, and they slowly increase in strength as they pass toward 
the pylories. The contractions have their origin in the wall of 
the organ itself, because they will continue for half an hour or 
more after removal of the viscus from the body and its preserva- 
tion in a bath of warm saline solution.’ The small ganglia in 
the wall of the stomach probably coordinate the contractions. 
Although the gastric contractions are of autocthonous origin, 
they are subject to control of the central nervous system by 
means of the vagus nerve, especially of the left vagus nerve. 
On stimulating the peripheral end of the vagus nerve, the tone 
of the gastric muscle is usually at once much diminished. Any 
gastric contractions are usually then abolished. Shortly after 
this, on the contrary, renewed movements set in, often very 
vigorous in character, and usually about four times as powerful 
as the contractions during ordinary digestive activity. Thus the 
first effect of stimulation of the vagus is inhibition of the gastric 
tone, the second is increase of tone and augmentation of move- 
ment. Stimulation of the central end of the vagus produces a 
slight inhibitory effect upon the stomach if the other vagus nerve 
is intact. The splanchnic nerve was not found to exert any in- 
fluence upon the musculature of the stomach, either in the direction 
of augmentation or of inhibition. Occaslonally some inhibition 
of gastric movement is excited by the stimulation of the 
splanchnic, but this not usually ; such occasional results are due 
probably to the vaso-constriction produced by the splanchnic 
