POPULAR SCIENCE REVIEW. 
321 
can be burnt as easily and with as good results as lumps ; coke and cinders 
may be burnt over and over again, until they become as fine as sand. The 
ashes from the fire all drop through the bottom of the grate into or through 
the air-chamber, consequently dust from the fire is greatly diminished in 
the room ; the draught may be regulated at pleasure with a valve. The 
invention may be easily applied to many existing grates at the cost of a few 
shillings. 
MEDICAL SCIENCE. 
The Localization of Function in the Brain. — Dr. David Perrier has 
given a valuable abstract of a paper read before the Eoyal Society. It is 
published in abstract in the “ Proceedings of the Eoyal Society,” vol. xxii. 
•No. 151. He says that among the experiments now related are some in 
further confirmation and extension of those already made on cats, dogs, and 
rabbits, as well as a new series of experiments on other vertebrates. In 
particular, numerous experiments on monkeys are described, for the purpose 
of which the author received a grant of money from the Council of the 
Eoyal Society. In addition, the results of experiments on jackals, guinea- 
pigs, rats, pigeons, frogs, toads, and fishes are narrated. The method of in- 
vestigation consists in the application of the stimulus of an induced current 
of electricity directly to the surface of the brain in animals rendered only 
partially insensible during the process of exploration, complete anaesthesia 
annihilating all reaction. It is supplemented by the method of localized 
destructive lesions of the hemispheres. Special attention is called to the 
precision with which a given result follows stimulation of a definite area — 
so much so, that when once the brain has been accurately mapped out, the 
experimenter can predict with certainty the result of stimulation of a given 
region or centre. The theory that the phenomena are due not to excitation 
of cortical centres, but to conduction of the electric currents to basal ganglia 
and motor tracts, is considered to be disposed of by the fact of the precision 
and predictable characters of the results, and by the marked differences in 
the phenomena which are observed when regions in close local relation to 
each other are excited. Other facts are pointed out bearing in the same 
direction ; among others, the harmony and homology subsisting between the 
results of experiment in all the different animals. The experiments on 
monkeys are first described. Eeference is continually made in the descrip- 
tion to figures of the brain, on which are delineated the position and extent 
of the regions, stimulation of which is followed by constant and definite 
results. A complete statement of these results in the present abstract is 
impossible. Generally, it may be stated that the centres for the movements 
of the limbs are situated in the convolutions bounding the fissure of Eolando, 
viz. the ascending parietal convolution with its postero-parietal termination 
as far back as the parieto-occipital fissure, the ascending frontal, and 
posterior termination of the superior frontal convolution. Centres for 
individual movements of the limbs, hands, and feet are differentiated ill 
these convolutions. Further, in the ascending frontal convolution, on a 
level with the posterior termination of the middle frontal, are centres for 
VOL. XIII. — NO. LII. 
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