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POPULAR SCIENCE REVIEW. 
marls, of 18 feet 6 inches ; he was not able to discover any trace of Am- 
monites planorbis, nor of any of the peculiar limestones indicating the 
“ Insect” and “ Saurian ” zones. He found one fragment of bone-bed lying 
loose at the end of the Lane, and containing characteristic fish-remains ; but 
though he searched carefully, he could not find in situ the bed from which 
it had been detached. — Yide The Reader , December. 
MEDICAL SCIENCE. 
The Congelationof Animals. — It is generally supposed that certain animals 
cannot be frozen without the production of fatal results, and that others can 
tolerate any degree of congelation. Both these views have been shown to be 
incorrect in a paper read before the French Academy, by M. Pouchet. The 
writer arrives at the following conclusions : — (1.) The first effect produced by 
the application of cold is contraction of the capillary blood-vessels. This may 
be observed with the microscope. The vessels become so reduced in calibre 
that the blood-globules are unable to enter them. (2.) The second effect is 
the alteration in form and structure of the blood-globules themselves. These 
alterations are of three kinds ; (a) the nucleus bursts from the surrounding 
envelope ; (b) the nucleus undergoes alteration of form ; (c) the borders of 
the globule become crenated, and assume a deeper colour than usual. (3.) 
When an animal is completely frozen, and when, consequently, its blood- 
globules have become disorganized, it is dead — nothing can then reanimate 
it. (4.) When the congelation is partial, those organs which have been com- 
pletely frozen become gangrenous and are destroyed. (5.) If the partial 
congelation takes place to a very slight extent, there are not many altered 
globules sent into the general circulation ; and hence life is not compromised. 
(6.) If, on the contrary, it is extensive, the quantity of altered globules is so 
great, that the animal perishes. (7.) On this account an animal which is 
partially frozen may live a long time if the congelation is maintained, the 
altered globules not entering into the general circulation ; but, on the con- 
trary, it dies if heat be suddenly applied, owing to the blood becoming 
charged with altered globules. (8.) In all cases of fatal congelation the 
animal dies from decomposition or alteration of the blood-globules, and not 
from stupefaction of the nervous system. 
The Development of Muscular Fibre. — In the Proceedings of the Royal 
Society, a paper appears containing some new views. It is written by Dr. 
Wilson Fox, of University College, and is intended less or more as an argu- 
ment in favour of the cell theory ; but it will be seen by those who understand 
the views of Huxley and modern writers, that it is really an advocacy of the 
periplast view. According to Dr. Fox’s observations, the earliest form in 
which muscular tissue appears in the tadpole, is an oval body coontaining 
a few nuclei, and packed closely with pigmentary granules. From the well- 
defined outline of this body the writer is disposed to regard it as a cell though 
he has not been enabled to isolate any limiting membrane or cell-wall. 
These bodies increase in length with or without multiplication of their nuclei, : 
and, after a short period, a portion of their structure loses, in great part, its 
