DeEcEMBER 10, 1896] 
NATURE 
followed by one on the ‘“‘ Preparation of keeping milk, 
fermented milk, and the bye-products of milk.” The 
economic aspects of dairying are next dealt with, and a 
concluding chapter is devoted to margarine and mar- 
garine cheese. 
The definition of milk, with which the book opens, 
seems to lack those qualities of precision which should 
characterise a definition. What kind. of notion would 
the following words convey to a reader who knew nothing 
about milk ?— 
“ By milk, in the widest sense of the term, is under- 
stood the secretion of the special glands of the female 
mammal. It is a white, opaque liquid, of the character 
of an emulsion, with a faint odour and a slight flavour ; 
and it is produced during a longer or shorter period after 
parturition. It consists chiefly of water, fat, casein, 
albumin, milk-sugar, and mineral salts, and is specially 
adapted for the sustenance of the young.” 
That milk “consists chiefly of water” we know; but 
had the translators been on the alert, they would have 
suppressed the word “chiefly” in the foregoing passage. 
The difficulties of translation, indeed, are exemplified in 
various unhappy phrases, as, for instance, when keeping 
milk is defined as milk which “ possesses the property 
of being able to keep.” 
A point about which there has been much controversy 
—the existence or not of an enveloping membrane 
upon each of the fat globules in milk—is dealt with 
emphatically enough :-— 
“The fat globules are not surrounded with a mem- 
branous envelope. Owing to the action of molecular 
force, the little globules are surrounded by a thin watery 
covering of serum, and act very much as if they were 
actually surrounded by a membrane.” 
Dairy farmers, and many who are not dairy farmers, 
will be puzzled by a statement, which apparently has 
been casually dropped in on p. 21, concerning the im- 
petus which a globule receives through its weight and 
centrifugal force ; there is at least novelty in the idea of 
the “centrifugal force” of a fat globule of milk. On 
p. 46 is another statement which will certainly startle all 
experienced feeders of dairy cattle; it is to the effect 
that “milk cows must not be fed with beans, peas, 
lupines, pea-straw.” Of feeding with lupines we do not 
know much in this country ; but as to the other materials, 
a footnote shows that even the translators felt uneasy, and 
it is regretable that they did not suppress the passage. 
The author recommends, in the winter feeding of butter 
cows, the moderate use of beet, in conjunction with other 
foods. This, of course, is perfectly intelligible to a 
German farmer ; but the translators should have added 
that for all practical purposes the English mangel is 
competent to take the same place in the food as the 
German beet. The feeding of cows, indeed, is a subject 
which might well have been treated more fully. This 
section contains a statement which we cannot forbear 
quoting. for it relates to a matter of as much practical 
interest to the dairy farmer as of scientific interest to the 
physiologist. On p. 42, the author says :— 
“There can be no doubt that, in the case of cows yield- 
ing a large amount of milk, the fat derived from the 
food is utilised for the formation of milk-fat.” 
The nature of the few criticisms we have made should 
render it obvious that a free translation and adaptation 
NO. 1415, VOL. 55] 
| of Fleischmann’s work would have been more valuable 
than the very literal translation that has been provided. 
Many of the woodcuts—of which there are eighty-five, 
besides half-a-dozen full-page plates—are different from 
those in the German original, and it is matter for regret 
that the same latitude was not allowed in connection 
with the text. It cannot be doubted that the translators 
possess the knowledge and skill essential to the pro- 
duction of a serviceable adaptation, and their description 
of—for example—the-manufacture of Cheddar cheese in 
this country would probably have differed considerably 
from that of which they have laboured hard to furnish a 
word-for-word rendering. Viewing the book as a whole, 
it is not one to put into the hands of a beginner. A 
discriminating reader, however, who already possessed 
some knowledge of the subject, would peruse its pages 
with profit. 
OUR BOOK SHELF. 
Elementary Geology. By G. S. Boulger, F.L.S., F.G.S. 
Pp. viii+ 180. (London and Glasgow: William Collins, 
Sons, and Co., Ltd., 1896.) 
Dr. W. S. Davis’ “ First Book of Geology” has been re- 
written and revised throughout, and transformed by Prof. 
Boulger into the text-book now under notice. The chief 
criticism we have to offer upon this metamorphosed 
volume—and ‘the criticism applies to most elementary 
text-books—is that details are dealt with much too early. 
Four pages in the present volume are devoted to general 
remarks on the objects and methods of geology, geolo- 
gical evidence, and divisions of the subject ; and about five 
pages to descriptions of the form and size of the earth, 
terrestrial movements, the nebular theory, the probable 
condition of the interior of the earth, and the cause of the 
Glacial period. The nature of the descriptions may be 
gathered from the statement of the limited space occu- 
pied by them. Of this brief treatment of large subjects 
we do not, however, enter a complaint, for the book is 
intended principally for pupils connected with the De- 
partment of Science and Art, and, regretfully though we 
say it, these pupils like concentrated essence of facts, which 
can be assimilated with the smallest possible mental exer- 
cise. Such readers may develop a mild kind of interest 
in the first nine pages of the book ; but then comes the 
pons asinorum of text-book geology—the account of rock- 
forming minerals and their distinctive characters. Why 
should such a paragraph as the following be put before a 
beginner in geology ? 
“Sulphur unites with many metals to form su/phides, 
including the abundant iron-pyrites (FeS,), and many im- 
portant metallic ores, such as chalcopyrite, galena, and 
blende, ores of copper, lead, and zinc respectively. 
Chlorine with sodium forms the abundant ch/oride, 
common salt (NaCl). Iron forms two oxides, the ferric 
oxide (Fe,O,), which occurs as hematite and hydrated as 
limonite, both important ores, and the ferrous oxide (FeO), 
while both occur in the black oxide, magnetite (FeO, 
Fe,O,, or FegO,). The oxide of aluminium (Al,O;) is 
called alumina, that of calcium (CaO), dime, that of 
sodium (Na,O), soda; that of potassium (KO), potash ; 
and that of magnesium (MgO), magnesia; and these 
oxides and those of iron are, when in combination, known 
as dases. In combination with acids they form sa/¢s ; 
with silicic acid (H,SiO,), silicates ; with carbonic acid 
(H,CO,), carbonates ; with sulphuric acid (H,SO,), sul- 
phates. The majority of rock-forming minerals are 
silicates.” 
It seems to us to be a great mistake to assume 
that young students of geology possess sufficient know- 
