422 
NATURE 
[March 1, 1883 
motor cell in the brain. When s is stimulated by a 
slight touch, the stimulus is transmitted up to s, thence 
to M, and down m to muscles, thus causing reflex con- 
traction. This is increased when a number of slight 
touches are made over a limited surface, as in tickling, 
because then s and S’‘are both stimulated, and more 
motor impulses are produced. But when harder pressure 
is made on s the stimulus, instead of being confined 
to S, is transmitted to S’ and thence to M, as well as 
direct from sto M. Thus two impulses are sent to mM, 
which, starting at the same time from s, have had a 
different length to travel round. This different length, 
we suppose, is just sufficient to allow the impulses to 
interfere with one another in M and thus destroy each 
other’s action in regard to motion. When 3’ is also irri- 
tated at the same time as s, the same interference is pro- 
duced by a stimulus passing from s’ to $s", and then to M’. 
But at the same time that the relation of s’ Ss” to M and 
M’ is such as to produce interference and inhibition in 
regard to motor impulses, the relation to each other is 
such that the impulses mutually strengthen one another 
on their way up to the brain, and thus the sensation 
which we perceive on firm pressure is more definite and 
better localised. 
On this hypothesis each successive layer of sensory 
and motor cells in the spinal cord may have several 
different functions: (1) Each cell may exercise its own 
sensory or motor functions in relation to the sensory 
or motor nerves connected with it; (2) it may exercise 
an inhibitory function on the sensory and motor cells 
above or below it, and also on other sensory or motor 
cells on the same plane with itself ; (3) it may have a 
stimulating function on other cells above, below, or on 
the same plane as itself, increasing instead of abolishing 
their action. 
The effect that any sensory or motor cell produces when 
stimulated is not determined then simply by the profer- 
ties of the cell itself, but by its eZa¢éons to other cells or 
fibres. 
Motion, sensation, inhibition, or stimulation are not 
positive, but simply relative terms, and stimulating or 
inhibitory functions may be exercised by the same cell 
according to the relation which subsists between the 
wave-lengths of the impulses travelling to or from it, the 
distance over which they travel, and the rapidity with 
which they are propagated. 
T. LAUDER BRUNTON 
(To be continued.) 
NOTES 
M. JANSSEN was present at the sitting of the Academy of 
Sciences on Monday, for the last time before his departure from 
Paris. He is very busy preparing his apparatus. 
Baron NORDENSKJOLD so very carefully considers every step 
he takes that we may be sure he has satisfactory reasons for 
claiming the reward of 25,000 guilders (about 2000/.) offered 
by the Dutch three centuries ago to the discoverer of the 
North-east Passage. Some surprise is expressed at the Baron’s 
claiming a reward which lapse of time may be considered as 
having rendered obsolete. At the time it was offered the North- 
east Passage was regarded as a sea-route of the highest com- 
mercial importance, though this idea has been long exploded. 
Still to some extent Baron Nordenskjéld has shown that the old 
conception was not without justification, and although the pas- 
sage is now of no value as a route to China and India, still the 
Swedish explorer has proved that as a trade-route it may be 
rendered of considerable yalue. Moreover as he is so dis- 
interested, ardent, and successful a pioneer of science, we should 
be glad if the Dutch Government cheerfully admitted the claim. 
It may be remembered that the much larger reward offered by 
our own Government to the discoverer of the North Pole was 
withdrawn many years ago. 
AT the last meeting of the Royal Swedish Geographical 
Society, on the proposal of Baron Nordenskjold, the greatest 
honour at the disposal of the Society, the Vega gold medal, was 
conferred on Mr. Stanley. The medal, struck 7” memoriam of 
the Vega expedition ‘‘for geographical discovery,” has only been 
twice before conferred—viz. in 1881, on Baron Nordenskjéld, 
and in 1882, on Capt. Palander. 
In 1880 the Belgian Academy proposed, as a prize-subject, 
the relations between physical and chemical properties of simple 
and compound bodies (completion of the knowledge of these by 
new experiments). The prize (a gold medal valued at 1000 franes) 
has been awarded to M, De Heen, engineer at Louvain. His 
memoir is an extension of one previously sent in, which gained 
high approbation for original work and results, but was thought 
badly-proportioned, so that the subject was re-proposed. ‘The 
work is in five sections, dealing successively with specific heats, 
dilatability of solids and liquids by heat, changes of state in rela- 
tion to chemical composition, capillarity, and (here without 
original researches) molecular volumes, refraction, spectral analy- 
sis, and absorkent power of bodies for heat. The ample vésemé 
M. Spring gives of this memoir (Bu//. Belg. Acad. No. 12) 
indicates matter that must be of much interest and value to the 
physicist and the chemist. 
PERHAPS never in the history of science, the Zazcet says, has 
a distinguished career equalled in its length that of M. Chevreul, 
whose name is best known in this country in connection with his 
investigations on colour; and it is probably altogether unique 
for a savant to be able, at one of the most distinguished scientific 
societies in the world, to refer to remarks which he made before 
the same society more than seventy years previously. A few 
days ago M. Chevreul made a communication to the Academie 
des Sciences, and at its close he observed : ‘* Moreover, gentle- 
men, the observation is not a new one to me. I had the honour 
to mention it here, at the meeting of the Academie des Sciences, 
on the roth of May, 1812”! 
THE death is announced of the Silesian botanist, Herr Johann 
Spatzier, aged seventy-seven ; also of Herr Josef Knorlein, the 
entomologist, at Linz, on February 12, aged seventy-seven. 
MountT ETNA is very active and ejects red-hot lava. At 
night the glare is constantly visible. A violent shock occurred 
on February 15. 
WE find in the last number of the J/evestia of the Russian 
Geographical Society a note, by Prof. Lenz, on the cosmical 
dust collected by M. Marx at the meteorological station of 
Yeniseisk. After having vainly searched for traces of cosmical 
matter, as he was advised to do by Baron Nordenskjold, he dis- 
covered it finally on October 31, 1881. The wind was blowing 
in the evening with great force from the west, and during the 
night it turned into a strong gale, with some snow and rain. 
When M. Marx measured next morning the amount of water in 
his pluviometer, he remarked that it had a considerable quantity 
of suspended matter of a brick-red colour. After careful analysis 
this matter proved to consist of iron, nickel, and cobalt. Prof. 
Lenz does not doubt that the red dust found by M. Marx had a 
cosmical origin, and points out that it was observed on a day 
very near to the appearance of the November meteors. 
At Monday’s meeting of the Paris Academy of Sciences, 
M. Tresca read a paper full of facts on the experiments 
tried at the Gare du Nord. Deducting certain work for the 
, mechanical transmission to the generator, the result was 42 per 
‘ cent. of energy conveyed instead of 35 per cent. with a smaller 
