FEBRUARY 15, 1901.] 
able experiments, with those of Butschli, Hardy 
and others, have shown how much caution is 
necessary in the interpretation of the coagulated 
material observed in sections ; but they have 
produced in some minds a pessimism regarding 
the morphological investigation of the cell that 
is without justification. The cyclical changes 
observed in sections of fixed material are not a 
matter of chance, but form a highly significant 
connected series, and many of them have been 
fully confined by comparison with the living 
material. The experiments in question have 
provided us with a valuable critique of our 
methods, but have not destroyed their value. 
Even though we may not agree with all the 
conclusions set forth in the present paper, we 
must regard it as weighing heavily on the side 
of the view that the cell possesses a definite and 
complex morphological organization that passes 
through perfectly ordered cyclical changes, and 
of which our cytological methods give us not in- 
deed a photographic image, but still a definite 
record. EDMUND B. WILSON. 
Elements of Mineralogy, Crystallography and Blow- 
pipe Analysis. By ALFRED J. Moses and 
CHARLES L. Parsons. New York, D. Van 
Nostrand Co. 1900. 
The edition of the book before us is in plan 
essentially like the former edition of 1895. 
Many parts have, however, been re-written and 
considerable additions are to be noticed in text 
and illustration. 
The part devoted to crystallography has 
undergone complete revision, and in its treat- 
ment of the subject conforms to the prevailing 
classification. Over one hundred figures, for 
the most part excellent, have been added and 
we are pleased to note a new chapter treating en- 
tirely of twin crystals. The chapters on blow- 
pipe analyses treat of the apparatus used in, 
and the operations of, blowpipe analyses. A 
summary of blowpipe tests is also given with a 
short scheme for qualitative blowpipe analysis. 
The descriptive mineralogy opens with chap- 
ters treating of the various characters of miner- 
als, that on optical characters being intended 
as introductory to a subsequent study of miner- 
als in thin sections under the micrascope. In 
the part describing the individual minerals we 
SCIENCE. 
267 
find them grouped according to the economic 
classification, viz., iron minerals together, 
copper minerals together, etc. Before each 
group a brief discussion is made of the uses of 
the particular metal in hand, the minerals from 
which it is obtained and the metallurgical proc- 
esses involved in its production. We think 
this an excellent feature of the book. The 
silicates do not yield to such a classification and 
are grouped according to the usual chemical 
classification. While the descriptive part as 
a whole and in many of its details seems to 
us excellent and worthy of commendation, we 
can not but express our regret that it should be 
marred by so many poor illustrations. The 
crystal drawings are excellent, but with few 
exceptions the other illustrations are not what 
they should be. It is doubtless difficult to rep- 
resent the characteristic appearance of a mineral 
on paper and unless great pains is taken in this 
regard it were better for both books and mineral- 
ogy not to attempt such illustration. 
In describing the crystallization of the min- 
erals we notice that the real angle between the 
crystal faces are given instead of the supple- 
mentary angle as is customary. As the latter 
angles are the ones most convenient for use in 
calculation it would seem desirable to have had 
them given. 
The book is concluded by a series of tables 
designed for the rapid determination of the 
common minerals. C. H. W. 
A Text-Book of Important Minerals and Rocks. 
By 8S. HE. Tirtman. New York, John Wiley 
and Sons; London, Chapman & Hall. 1900. 
Professor Tillman has prepared this book 
with the idea of furnishing the general student 
of mineralogy with a convenient and service- 
able book, condensed in form, yet sufficiently 
complete in descriptive matter to equip the 
student with a good general knowledge of the 
subject. 
The opening chapter consists of a very brief 
outline of the crystallographic character of 
minerals. The second treats of other physical 
characters and of the chemical properties of 
minerals. With the latter is included a brief 
description of blowpipe and chemical tests. 
That four pages should be deemed sufficient for 
