428 
NATURE 
| Feb. 24, 1870 
The first and third divisions of this work seem 
unexceptionable ; but the more purely botanical portion 
might be improved by revision, thus, for instance, at 
p. 178, cystoliths and crystallised concretions in plant- 
cells are treated of in a manner which suggests want of 
familiarity with the microscopic examination of plants, 
and is calculated to make a beginner suppose all the 
crystalline concretions of plants are cystoliths of some 
sort. 
At p. 216, it is stated that “In some cases, cells consist 
only of protoplasm and nucleus, being destitute of cell- 
walls during a portion or the whole of their existence,” and 
a single line might have been added to explain the ex- 
ceptional conditions under which these cells—that are 
not cells—present themselves. Again, at p. 218, after 
the passage “many cells are altogether empty, and 
consist of nothing but the cell-wall,” there might have 
been added “after cessation of the functions.” 
The Screw pine referred to at p. 227 is not a palm; 
and while the term “imbricated buds” is awkward, the 
reference, on the same page, to roots that have no buds 
seems to suggest that buds are generally present on roots 
inconsistently with what precedes. 
Before concluding the notice of this work we must refer 
to one part of the introductory chapter, where the author 
very justly condemns as a delusive error the notion that 
there is any opposition or conflict between science and 
art, or between theory and practice. “ They are, as they 
ever have been, and ever must be, in the fullest harmony. 
If they appear to jar or stand in contradiction, it is 
because we have something false or incomplete in what we 
call our science or our art; or else we do not perceive 
correctly ; but are misled by the narrowness and aberra- 
tions of our vision. It is often said of a machine, that 
it is good in theory, but fails in practice. This is as 
untrue as untrue can be. If a machine fail in practice, 
it is because it is imperfect in theory. It should be 
said of such a failure—the machine was good, judged 
by the best theory known to its inventor, but its inca- 
pacity to work demonstrates that the theory had a 
flaw.” 
It is the boast of some who affect to glory in the suff- 
ciency of practice and to decry theory, that the former is 
based upon experience, which is the only safe guide. But 
this is a one-sided view of the matter. Theory is also 
based upon experience, if it be truly scientific. The vague 
surmise of an ignorant and undisciplined mind is not 
theory. Theory, in the proper and good sense, is always 
a deduction from facts—the best deduction of which the 
stock of facts in our possession admits. It is the inter- 
pretation of facts. It is the expression of the ideas which 
facts awaken when submitted to a fertile imagination and 
well-balanced judgment. 
If the appreciation of these views were at all equal to 
their truth, and if the importance of their bearing on the 
advancement of agriculture were at all adequately recog- 
nised, there would probably be little reason to lament the 
want of attention either on the part of the farmer or the 
statesman, to the scientific aspects of that pursuit, and less 
scope for that blatant obstructive, the “ practical man,” who 
shuts his eyes and ears against everything his grandfather 
did not know of, believes only in the folly of wisdom, and 
is supremely happy in his own ignorance. 
OUR BOOK SHELF 
A Geographical Handbook of all known Ferns, with 
Tables to show their Distribution. By K. M. Lyell. 
(Murray, 1870.) 
THIS useful and unpretending, but elegant little volume, 
consists of two parts. In the first, the genera and species 
of ferns are enumerated under a number of geographical 
divisions and subdivisions, which appear to have been 
judiciously selected. The stations, habitats, and 
geographical range of each species, are given with much 
care, and the authorities fully quoted. It thus forms a 
series of fern catalogues for eighteen divisions of the 
globe. The second part consists of a systematic list of 
all the species, with their range of distribution indicated 
in eighteen columns. Sir William Hooker’s arrangements 
and limitations of species have been followed throughout, 
and this gives a unity to the work which has its value. 
But as ferns have generally so wide a range that genera 
restricted to any one part of the globe are exceptional, we 
think it would be as well in a work of this nature, to adopt 
the additional genera of John Smith and others. 
We would also suggest for another edition, that a sum- 
mary of the genera and species might be usefully given at 
the head of each geographical subdivision. Thus for 
“Europe Proper” we should have : 
1. Woodsia 2 species | 13. Asplenium . F7 species 
2), Dicksoniayya ys 14. Scolopendrium. 2 ,, 
3. Hymenophyllumi,, 15. Aspidium 55 
4. Trichomanes. I ,, 16. Nephrodium. Cues 
5. Davallia Tieton 17. Polypodium . Bh 35 
6. Cystopteris arms 18. Nolhochlena Byars 
7. Adiantum. Ques 19. Gymnogramme. 2 ,, 
8. Cheilanthes ZY oh | 20, Osmunda «. Tee 
g. Cryptogramme I ,, | 21. Ophioglossum . 2 ,, 
10. Pteris . Ayes 22. Botrychium . Yee 
11. Lomaria . ees — 
12. Woodwardia. 1 55 species 
” 
Such summaries would offer useful materials for com- 
parison, and show at a glance what genera were abundant, 
rare, or wanting, in a given district. We also think the 
specific names should have been printed with some 
difference of type, so as more readily to catch the eye; 
but these are small matters in so useful a work, which 
must have been a labour of love to its author, and which 
no lover of ferns should be without. A. R. W. 
Agricultural Analysis——Agvricultural Qualitative and 
Quantitative Chemical Analysis. After E. Wolff, 
Fresenius, Krocker, and others. Edited by G. C. 
Caldwell. Pp.vi.and 307. 8vo. (New York: Judd. 
London : Triibner, 1869.) 
Mr. CALDWELL (Professor of Agricultural Chemistry in 
the Cornell University) prepared this compilation for the 
use of his own pupils and agricultural students generally. 
Many of the chapters consist of translations from Wolff’s 
“Anleitung,” and much more is taken from Fresenius’s 
well-known works on analysis. The metric system of 
weights and measures, and the centigrade thermometric 
scale are adopted throughout ; and a useful, but not suffi- 
oo extensive set of tables is given at the end of the 
work. 
The merit of a treatise of this kind consists in a proper 
selection and arrangement of materials ; and Prof. Caldwell 
seems to have performed his task satisfactorily, though, as 
he admits, somewhat hastily. It is hardly necessary to 
add, that the book would be quite as much out of place 
in the hands of an unassisted student as any of those of 
which it is an adaptation. Under the guidance of a 
teacher, however, it would undoubtedly be of much service 
in an agricultural laboratory. 
Jahrbuch der Exfindungen. ". Hirzel und H. Gretschel. 
(Leipzig : Quandt und Handel, 1869.) 
THIS is one of a type of books which is not published in 
this country, {either because our publishers are not suffi- 
ciently energetic, or because our public has not as yet 
