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POPULAR SCIEXCE REVIEW. 
whicli exists in the limestone deposits ; and, by similar mode of reasoning, 
that the deposits of carbon could not have been derived from the primary. 
He is modest enough to content himself with attacking an existing theorj' with- 
out supxDlying a substitute, and in this particular he difiers from most scien- 
tific sceptics. We think, however, that his assumption of the absence of 
elevation of land in the beginning is utterly unjustifiable, and that his conse- 
cjuent conclusion that the planet’s area is increased, is little better than absurd. 
At all events, his reasoning is exceedingly ingenious, and since he draws 
attention to phenomena and facts that have been too little investigated in 
this country, his pamphlet will, if read, be of some service, though not in 
the direction its author would wish. 
The Supply of Fuel in Ireland. — Under this title a very imi^ortant and 
lengthy memoir appears from the j^en of Mr. H. O’Hara, C.E., in the Dublin 
Quarterly Journal of Science for October. He concludes that the supply of 
coal in Ireland is far from being exhausted, and that the cpiantity of peat is 
larger than is generally believed, and only requires to be worked and pre- 
pared on other principles than those now adopted, in order to make a most 
valuable addition to the national resources. 
MEDICAL SCIENCE. 
The Structure of the Cerebellum. — So much progress has of late been made 
in the direction of histology, and so great has been the modification of views 
universally accepted a few years since, that it becomes necessary to record 
carefully the observation of all writers upon microscopic anatomy. Among 
recent contributions to the study of the minute structure of the central 
nervous system, few are more interesting than the published investigations of 
M. Luys, who states with regard' to the cerebellum : — 
1st. That this organ and its dependencies form a sub-system very accu- 
rately isolated in the general assemblage of the fibres of the nervous system. 
It is only by the intervention of the fibres of its peduncles that it enters into 
combination with the cerebrum, and propagates its action to the grey sub- 
stance of the corpora striata. 
2nd. Its white fibres pass out of the grey cortical substance as clearly 
defined filaments, and appear to be composed after their origin by the con- 
tinual addition of prolongation of nerve-cells of various descriptions. 
3rd. All the white cerebellar fibres, whatever be their point of emergence, 
are directed as rays toward a mass of grey substance at the centre of each 
cerebellar hemisphere to reach the nerve-cells which are there. 
4th. From this common centre of convergence these soon pass forwards, in 
three directions, as series of secondary fibres, true efferent conductors, which 
go to distribute themselves among the bundles of spmal ascending fibres, and 
thus as they decrease, little by little, become the origins of the grey peri- 
pheral substance of the cerebellum. 
5th. All these efferent offsets are intercrossed ; they are distributed hi the 
periphery to the opposite side from that in which they originated. 
6th. The lowermost efferent fibres, directed from above downwards, and 
from behind forwards, take a sphral course through the spinal fibres, and are 
lost in the net-work of ceils of the olivary body of the opposite side. 
