“Tia 
390 
‘selection: for, admitting Professor Brooks’s 
doctrine, that each individual inherits all the 
characteristics of the species, and that the 
female function prevents the development of 
the male characters though they may appear 
when that function is destroyed), it is plain 
that those characters are either incompatible 
with the female function or useless to the 
female, and hence there is no reason why she 
should acquire them; while their presence in 
the male, to which they are of obvious advan- 
tage, is in most cases to be accounted for 
by sexual selection. On the other hand, it 
is obvious that all the complex apparatus 
of uterus, placenta, and similar organs, must 
have originated with the female. We cannot 
agree with Professor Brooks, that the presence 
of mammae in the male is an indication that 
the mammary function was originally a male 
characteristic, any more than that the presence 
of rudimentary stridulating organs in female 
Orthoptera shows that these were first acquired 
by the female. Why should Professor Brooks 
adopt exactly opposite explanations for pre- 
cisely parallel cases? 
The propagation of cells by means of gem- 
mules is not only purely hypothetical, but, ap- 
parently at least, opposed to what we know of 
the mode of cell-formation. Cells arise only 
by division of some pre-existing cell, and 
never seem to arise spontaneously, as would 
very probably be the case if their propagation 
by gemmules were at all common. Nor does 
the process of impregnation, as actually ob- 
served, lend support to the new hypothesis ; for 
the head of the spermatozoon coalesces with 
the nucleus of the ovum, apparently without 
loss of bulk, or in any way indicating an emis- 
sion of gemmules. The influence of the male 
element seems rather to consist in modifying 
the action of the egg-nucleus. 
Mr. Conn’s very obvious objection (given 
on p. 294), that in many cases unfavorable 
conditions would not act upon certain cells, 
causing them to emit gemmules, but would 
result in the destruction of the animal, seems 
entitled to more weight than the author is in- 
clined to give it. Any hypothesis that fails 
to account for so large and important a class 
of facts cannot be called complete. 
Want of space compels the omission of many 
other objections, as well as the consideration 
of Professor Brooks’s views on_ reversion, 
natural selection, and the intellectual differ- 
ences between men and women. 
But, in spite of all that has been said, 
Professor Brooks is entitled to the thanks of 
all students of biology for his clear statement 
SCIENCE. 
-chemistry ’ was retained. 
Ju 
| Vou. TIL; No. 60. 
of the problem, and the many suggestive fields 
for investigation here opened. The student 
of heredity will find in this book just what he 
needs to give him a clear conception of how 
the problem is to be attacked. The book is 
one of remarkable ability. The way in which 
apparently disconnected series of phenomena 
are brought together and shown to be special 
cases of one general principle, is indeed mas- 
terly. Even if every single proposition of the 
hypothesis should prove to be without founda- 
tion, and the hypothesis entirely untenable, 
Professor Brooks must always be credited with 
having made a most important step in advance. - 
Assuming that the problem of heredity is at 
all capable of solution, some such preliminary 
clearing of the field is a necessity. If different 
observers will devote their energies to follow- 
ing up the various lines of inquiry which Pro- 
fessor Brooks has so ably suggested, we may 
be sure of most valuable and fruitful additions 
to our knowledge. To use Mr. Lewes’s words, 
‘even should the hypothesis prove a will-o’- 
wisp, it is worth following if we follow cir- 
cumspectly, for it hovers over lands where we 
may find valuable material. As an hypothesis, 
it so links together wide classes of facts that 
it may be a clew to great discoveries.’’ 
WATTS’S MANUAL OF CHEMISTRY. 
A manual of chemistry, physical and «organic. 
By Henry Warts. Philadelphia, Blakiston, 
1884. 16+4+595p. 8°. 
Frew text-books of chemistry have been more 
successful than the ‘ Manual of elementary 
chemistry ’ first published in 1845 by Professor 
George Fownes. Fownes, who was but thirty 
years of age at the time, held the chair of chem- 
istry in University college, London. His work 
had marked success from the very beginning, 
’and he was called upon to prepare three edi- 
tions in the succeeding four years. ‘The third, 
however, appeared posthumously ; for Fownes 
died in January, 1849, at the early age of thir- 
ty-four. Under the editorship of the late Dr. 
H. Bence Jones, and afterwards of Dr. A. W. 
Hofmann, the work appeared at frequent inter- 
vals in six editions; and, notwithstanding the 
constant additions of large amounts of new and 
important matter, the familiar name ‘ Fownes’s 
The tenth edition 
was edited by Dr. Bence Jones and Henry 
Watts, and appeared in 1868; another edi- 
tion, by Henry Watts, followed in 1872; and 
finally a twelfth, greatly increased in size, and 
issued in two volumes devoted to inorganic 
ae” = 
