1868. ] Zoology. 267 
positive pole. When the current is made to act on free acetic acid 
it concentrates the acid at the positive pole. He has also examined 
the action of the current on neutral tartrate of potash, on a mix- 
ture of tartrate and alkali, also on free tartaric acid. With the 
neutral tartrate, as soon as the current passes, the solution becomes 
alkaline at the negative pole; the principal result is the formation 
of a white precipitate at the positive pole. Analysis has shown this 
substance to be cream of tartar. The gas evolved at the positive 
pole was found to be composed of carbonic acid, oxygen, carbonic 
oxide, and nitrogen. When the current acts on a mixture of 
neutral tartrate and alkali the results are different. The gas 
evolved at the positive pole is then composed of carbonic acid, car- 
bonic oxide, oxygen, and hydride of ethylen: acetylen has also been 
detected in it. ‘he decomposition of free tartaric acid yielded the 
same products as the neutral tartrate, but in different proportions. 
Acetic acid was formed at the positive pole, and after an experiment 
had been in progress five days, a considerable quantity was isolated as 
acetate of baryta. 
12. ZOOLOGY—ANIMAL MORPHOLOGY AND 
PHYSIOLOGY. 
(Proceedings of the Zoological Society of London.) 
Morpuouoey. 
The Size of the Brain in Different Races of Men.—Dr. J. Barnard 
Davis has communicated a paper on this subject to the Royal 
Society. There has always been considerable difficulty in getting 
at a knowledge of the variation of the brain in various races, 
because it has been thought necessary to examine and weigh the 
brain itself, and this has not been done in the case of many exotic 
races. The method of gauging the skull cavity has been said to be 
of no real value, and hence has not been extensively applied. 
Dr. Davis shows that this is a mistake, and possibly the method of 
gauging is more reliable than that of weighing, for thereby the 
error likely to arise from the shrinking of the brain during fatal 
disease and from post-mortem changes is avoided. Dry Calais sand 
is used for gauging the brain-case, and an allowance of 15 per 
cent. is deducted for other structures present in addition to the 
brain. This amount has been very carefully estimated from a large 
series of observations. The sand is then weighed and reduced to 
its equivalent in cerebral matter of 1,040 specific gravity. Pro- 
fessors Tiedemann and Morton, who have made similar observations 
to those of Dr. Davis, omitted to make this allowance, and also (a 
much more important omission) did not discriminate male and 
female skulls. ‘This led to serious error, since the female brain is 
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