OcTOBER 16, 1902] 
NATURE 
603 
one million dozens and that, directly or indirectly, it 
gives employment to no less than 25,000 persons in 
London alone. 
In his historical sketch of the evolution of artificial 
mineral waters as we know them to-day, the author 
shows that progress has been made along two main lines- 
The existence of these popular beverages undoubtedly 
had its origin in the desire of the earlier physicians to 
prepare by artificial means saline solutions which should 
have the same therapeutic and curative effects as the 
waters obtained from well-known natural springs such as 
those of Epsom, Seidlitz or Bath. This necessarily in- 
volved some knowledge of the chemical nature of their 
constituents, and it was not, therefore, until Boyle had 
given birth to analytical chemistry, and Bergman had 
brought his genius and industry to bear upon the chemical 
examination of the waters from many of the mineral 
springs, that such imitation became possible. At the 
same time, much speculation was being indulged in as to 
the exact nature of that wonderful “ principle” which 
gave to many of the natural waters their sparkling 
character and piquant flavour; and the numerous re- 
searches which were being made in this direction 
culminated in the great discovery by Black of the 
chemical identity and true nature of carbonic acid gas. 
Along both these lines the author traces the gradual 
development of the mineral water industry, showing in 
true perspective and with due attention to their relative 
importance the various discoveries or steps by which its 
present position has been reached. In this connection, 
we think that the author has attached rather too much 
importance to Brownrigg’s share in the discovery of the 
true nature of carbonic acid gas, and has perhaps given 
too little prominence to the masterly researches and 
brilliant deductions of Black. In the main, however, the 
chapters dealing with the work of the earlier discoverers 
are accurately and clearly written, and the book should 
certainly be read by all who are desirous of acquiring an 
intelligent knowledge of the beginnings and development 
of this now important industry. 
There are, unfortunately, a few blemishes which ought 
scarcely to have escaped the author’s notice. Thus we 
are told on p. 3 that the latter half of the eighteenth 
century witnessed the birth of chemistry, while on p. 13 
that honour is assigned to the seventeenth. Whether we 
are to consider the former, the latter, or, indeed, either 
of these statements correct will naturally depend upon 
the precise meaning we are to give to the word “ birth,” 
but we presume that the author had in his mind the 
eighteenth century, which witnessed the labours of Black, 
Cavendish, Priestley, Scheele and Lavoisier, to mention 
only some of the giants who laid the foundation on 
which the wonderful superstructure of modern chemistry 
has been reared. 
The statement on p. 34 that “it is possible to-day to 
obtain by mechanical and other means water of as great 
chemical and bacterial purity as any natural water from 
the deep springs” presumably refers to filtration, but is 
not by any means clear. On p. 67 we are told that 
Macquer purified carbonic acid by passing it through a 
vessel “containing lime and water,” but are not told how 
much of the gas passed through. In connection with 
NO. 1720, VOL. 66] 
the use of sodium bicarbonate for the preparation of 
carbonic acid gas, the author makes, on p. 120, the truly 
astonishing statement that precautions have to be taken 
to prevent any avzmtonia present as an impurity from 
passing over with the gas into the gas holders. We 
should have thought, as a matter of fact, that the presence 
of the acid used for its decomposition would have con- 
stituted a sufficient “ precaution.” In one or two places, 
the language is a little involved, and there are several 
misprints and slips, such as Becheri for Becher on 
p- 42, Thiloria for Thilorier on p. 60, and unabsorbed 
would have been better than uma/tached on p. 120. The 
chapter on the syphon and its development is well written, 
and like the rest of the book is clearly illustrated by 
means of well-executed drawings. The author states in 
his prefatory remarks that he does not intend this to be 
a manufacturer’s handbook, and that therefore he has 
given no formulz for the preparation of the various 
waters. For the same reason, presumably, the descrip- 
tion of manufacturing processes and machinery is con- 
tained within the limits necessary to render the book 
acceptable to the general reader. It contains a good 
index and a well-compiled bibliographical table, and we 
can, in conclusion, heartily commend it “to all whom it 
may concern.” We cannot, however, help feeling that 
the author would have done well to have given his book 
a more independent character by dwelling with rather 
less emphasis on the excellence of the plant and manu- 
factured products of a particular firm. Avy GueGs 
DEVELOPMENT OF THE HUMAN EMBRYO 
By Dr. A. 
(London: Edward Arnold, 
Human Embryology and Morphology. 
Keith. Pp. viiit+ 324. 
1902.) Price 12s. 6d. net. 
R. KEITH is an accomplished anatomist, and in 
this morphological study of the development of 
the human embryo he has given us a valuable account, 
the result of wide and exact personal observation, of all 
the later phases of organogeny. 
The descriptions of the changes that occur during 
the formation of the face and neck, the alimentary tract, 
the central nervous system, the heart and blood-vessels, 
the history of the development of the skeleton and 
musculature of the head and trunk, are evidently the 
work of one who is thoroughly familiar with the anatomy, 
not merely of the human subject, but of the apes and 
other mammals as well; and in what we may term the 
“anatomical embryology” here set before us there is 
much which will be of permanent scientific worth, apart 
from what is of practical importance for the ordinary 
surgeon. 
From the other aspects, however, we regret that this 
treatise is less satisfactory. The earnest student who 
expects to find here a critical exposition of the thorny 
problems of modern embryology, or even a sufficiently 
accurate statement of the facts, will be sadly disappointed. 
The account of the formation of the germinal layers 
and of the early changes in the mammalian blastocyst 
is not only inadequate, it is erroneous ; we are told, for 
instance (p. 89), that “in lower vertebrates the mesoblast 
is entirely produced from the hypoblast,” and (p. 243) 
