42 QUATREFAGES, ON MAN AND THE LOWER ANIMALS. 
extended in certain groups and classes; although deficient in 
others, in the absence of the male element. Neither, 
however, in budding nor parthenogenesis is this power of 
growth unlimited; these processes stop after a certain num- 
ber of generations. Hence the importance of the male sex. 
The male clement regulates and imparts peculiar vitality to 
the ovum, probably by some chemical action; but how we 
are ignorant. The prominent distinction between geneagen- 
etic and parthenogenetic phenomena is, that fecundation in 
the former is at fixed intervals, whilst in the latter its absence 
is merely fortuitous, 
We particularly recommend the latter portion of the 
volume to the student, as we believe that here, for the 
first time, the various observations relating to ¢ruve par- 
thenogenesis have been placed in a collected and readable 
form. The last two chapters of the book are devoted to 
to general considerations, and a comparison of the geneagenetic 
phenomena of the animal and vegetable kingdoms. Our 
space will not permit us to do more than mention these, 
although we agree entirely with the views expressed, and 
admire the clear and readable style which the author uses. 
The following note, taken from p. 180 of this volume, can- 
not fail to interest microscopists :—‘‘ Notwithstanding the 
many improvements which the microscope has undergone for 
the last thirty years, it is still far from supplying the wants 
of histologists. In order to become accurately acquainted 
with many details, it would be necessary to have a magnifying 
power of from ten to twelve hundred diameters, with the same 
clearness and definition as one of three or four hundred 
diameters.” 
Much credit is due to Dr. Lawson for the discretion which 
he has shown in choosing such a book as this for translation, 
and also for the manner in which he has executed his task. 
It is, of course, impossible to render a scientific work from 
the French with the same grace and charm which characterise 
the original; but Dr. Lawson has done more than would 
have been deemed possible. He might, however, with advan- 
tage both to himself and his readers, have converted the French 
measures of length quoted in the volume, into corresponding 
English terms; a translation can hardly be considered complete 
without this, and the omission moreover might be regarded 
as arguing either ignorance on the translator’s part, or disre- 
gard for the comfort and enlightenment of a certain class of 
his readers, We cannot agree with the somewhat puerile 
strictures on the author made by the translator in his preface. 
The intimate association of metamorphosis and geneagenesis, 
