1880. | Recent Literature. 45 
are themselves determined by the incidence of variably potent 
forces which again interact variably, producing variable resultants, 
the propriety of expressing biological equations by x, y, gen- 
erations by x, and their variables by + x, powers of these or any 
other desirable arbitrary symbols, becomes apparent. The results 
to science of this method of treating the subject, while perfectly 
proper and right if a person chooses so to state them, may be 
fairly questioned. 
There seems just now to be a mania amongst biologists for 
re-naming things when they remodel old definitions. Although 
Huxley may define the individual as the result of the develop- 
ment of a single egg, and Haeckel define and call it a person, a 
virtual or an actual bion ; our author now under notice, thinking 
that, because it has recently been discovered that the ovicell, by 
impregnation, becomes blended with the spermatozoon, justifies 
him in coining a new term derived from that much-tortured 
Greek word from which so much dzology has been extracted, for 
re-christening the individual under the name of dad. The nomi- 
nal rubbish of scientific literature is acquiring huge proportions ; 
here. On this ground the proposition to re-name an old thing is 
ill-advised, and it may be doubted whether zygote, the name pro- ` 
posed for the result of the fusion of the male and female. cell 
elements in certain plants, by Strasburger, may not properly 
supercede diad, while the word gamete, proposed by the same 
author, will answer all practical purposes in designating the 
reproductive elements of separate sexes. When one is worried 
with getting at the import of some recently coined term, so often 
needlessly imposed by some of the evolutionary school of scien- 
tific thinkers, Haeckel and his followers especially, it is refreshing 
to turn to the pages of Darwin or Spencer, often to find the same 
questions treated in much better and plainer every-day En- 
glish.— 7. A. R. 
WILLiAMson’s Fers Ercuincs.—The dual character of this 
fine work makes it no less valuable to the amateur fern student 
and advanced pteridologist than to those who admire ferns for 
their beauty alone, as by adopting the geographical range of 
“ Gray’s Manual,” and accompanying his plates with descriptive _ 
text, the author, while professing only to present a series of life- 
like fern etchings, has really given to us a complete hand-book of 
all the species found growing in the Northern, Middle and East- 
ern States, and, in the present edition, the Dominion of Canada. 
clear, concise descriptions and faithful representations of 
the ferns themselves, will make this book an invaluable and indis- 
fern Etchings. By Joun WILLtamson, author of the “ Ferns of Kentucky.” 
Published by John P. Morton & Co., Louisville, Ky, 1879. 2d edition, 70 illustra- 
tions. Price $7.50. Riek ; 2 
