302 
eee ee. 
there is a large amount of needless repetition, for the 
estimation of the heat of combustion is a simple calcula- 
tion, which might have been made once for all with refer- 
ence to each proximate principle, especially since the bare 
facts, as they are put, convey but little idea to the general 
reader, The chemistry of foods is very superficially and 
imperfectly treated, not nearly so full as it deserves ; and 
the botany would have been better if a more thorough 
study of materia medica had been undertaken. There is 
one sentence we have in vain attempted to understand. 
When speaking of the sweet chestnut, the author, after 
remarking that at present it may be regarded as a luxury, 
says, “ The first step to a great extension of its use would 
be to make the ordinary horse-chestnut a safe and agree- 
able food, since it grows in our climate, and could be 
obtained in large quantities.” How this can be, seems 
extremely difficult to understand ; as is well known, the 
two fruits having nothing whatever to do with one 
another. 
The descriptions of the various methods that have been 
proposed for the preservation of meats which have to 
travel long distances and through hot climates is very 
complete and clear. The preference is given to the 
method of heating, and that adopted by Mr. Jones, in 
which the meat is heated in vacuo, to 280° F., in the cans, 
is fully described. It is shown, however, that by this 
process the meat is stewed, and over-stewed, not roasted 
nor boiled. In this, and all similar processes, it is found 
impossible to expel all the air without over-cooking the 
meat. 
Another subject of particular interest which is dis- 
cussed is the preservation of milk, Two methods, it 
appears, are adopted in America, one in which the milk 
is simply evaporated to one-fourth its original volume, 
when it will often keep for a month, and another in which 
sugar is added ; by the latter process it remains good for 
an indefinite time, and contains about one-third of its 
weight of sugar. The author agrees sufficiently with Dr. 
Daly in his condemnation of the employment of this pre- 
served milk for infants, to quote an article by him which 
appeared last year in the Lancet. 
Extract of meat, especially Liebig’s, occupies the greater 
part of one chapter, and we think the author has done good 
service in setting in a clear and unmistakable light the true 
value of that expensive luxury. He shows that its chief 
value depends on the meaty flavour it is capable of im- 
parting, and that its nutritive value is #2. He remarks— 
“Tts proper position in dietetics is somewhat more than 
that of a meat-flavourer, but all that is required for nutri- 
tion should be added to it. . . . Used alone for beef-tea 
it is a delusion.” That this is correct is evident from a 
consideration of the method by which it is prepared, for 
“during the process, all the ‘fat and as much of the 
gelatin and albumen as can be extracted are removed 
from the solution of flesh, whilst the fibrin, being insolu- 
ble, is necessarily left behind. Hence there remain water, 
salts, osmazone, and the extractives of flesh, or, in general 
terms, the flavouring matters and the salts of meat—thus 
leaving out all that is popularly (and correctly) regarded 
as nutritious.” 
Many tables are given to show the [effects of different 
substances on the respiration, pulse, exhalation of carbonic 
anhydride and aqueotis vapour, There seems to be a 
NATURE 
Sh 
‘¢ 
[Aug. 14, 1873 
want of association between the great mass of facts, 
which must have been the result of long and continuous 
labour ; and they are undoubtedly put forward in a way 
which is not best suited to convince the scientific student. 
For example, the effects on the pulse, &c., of tea dissolved 
in water is given in full, but under the head of water no: 
mention is made of its physiological action, though de- 
cidedly, by itself it changes the pulse rate, if nothin 
else. : 
Several recipes of the fourteenth century are quoted 
from “ Cury,” a copy of ancient manuscript recipes of the 
master cook of Richard the Second. There are also 
many scriptural references, and a very inappropriate ab- 
stract of an incident which occurred at the Worship Street 
Police Court. 
OUR BOOK SHELF 
A Manual of Metallurgy. By George Hogarth Makins, 
M.R.C.S., F.C.S., &c. (Ellis and White, 1873.) 
THE present edition of this work presents a marked im- 
provement over those which have preceded it, but it is 
still far from being all that even a small manual might 
be. In the preface the author expresses a hope that the 
volume, “in which the leading points connected with the 
principal metals are set forth, may be found useful,” and 
as there are singularly few metallurgical works in the 
English language, we have but little doubt that this hope 
will be realised. Mr. Makins has long enjoyed the repu- 
tation of being a most accurate assayer, and the descrip- 
tions of the processes of assaying gold and silver are 
careful and valuable. The portion of the work which is 
the least satisfactory is that devoted to iron. 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his correspondents, No notice is taken of anonymous 
communications. | 
The Huemul 
Tue Huemul of Chili and Patagonia, referred to in NATURE, 
pp. 253 and 263, was first recognised in modern scientific 
literature by MM. Gay and Gervais, who in the Annales des 
Sciences Naturelles for 1846 (v., p. 91), showed that the so-called 
Equus bisulcus of Molina, was a species of Deer (Cervus), which 
they proposed to call Cervus chilensis. ; 
In Gay’s “ Fauna Chilena” (plates 10 and rz), the female and 
skull are figured. Concerning the nomenclature of species, I 
have published some remarks in the last volume of the “ Annals 
of Natural History” (ser. 4, vol. vi. p. 213), to which I beg 
leave to refer such of your readers as are desirous of further 
information on this subject. P. L, SCLATER 
11, Hanover Square, W., Aug. 6 : 
Perception and Instinct in the Lower Animals 
In answer to Mr. George J. Romanes (NATURE, August 7) I 
beg to say that I particularly inquired of my friend whether he 
had been to or near his old house on the day the dog returned, 
or shortly before, and he assured me that ‘the had never been 
near it since he left.” I ought to have stated this in my 
account of the circumstance. 
I shall make no further remarks on the subject, because I be- 
lieve that nothing satisfactory can be arrived at till experiments 
of the nature indicated in my last letter have been systematically 
carried out, ALFRED R, WALLACE | 
Collective Instinct 
THE writer of one of the books on Indian sport relates how 
he saw a herd of antelopes, driven backwards and forwards by 
four wolves, which surrounded the herd, each guarding a diffes 
