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GENESIS, OR PARTHENOGENESIS ? 
BY H. E. FRIPP, M.D. 
LECTURER ON PHYSIOLOGY AT THE BRISTOL MEDICAL SCHOOL. 
T HE discovery of the “ viviparous larvation ” of the Aphis 
by Reaumur dates from the year 1738; that of the 
“ non-sexual multiplication ” of the Polype, by Trembley, from 
the year 1794. And now, in 1866, the most recent announce- 
ments in embryological discovery are those of M. Balbiani, 
who confirms the original suggestion of Reaumur that the 
Aphis is an androgynous insect ; and of M. Leuckart, who 
tells us of a new form of “ internal gemination,” the idea 
of which curious mode of reproduction was derived from 
Trembley^s observations on Hydra viridis. 
But let not the reader infer from these facts that the pro- 
gress of embryology has during this long interval either 
faltered or failed. As a science embryology is, perhaps, still 
far from being a connected body of laws and illustrations in 
which the exact relation between facts and principles has 
been established. But many important series of facts have 
been supplied in an empirical way by actual observation. 
And, although the analysis of these facts is not complete, 
generalizations have nevertheless been arrived at, which indi- 
cate with sufficient accuracy the essential nature of the repro- 
ductive function and of organic development as well as the 
influence of external force and matter upon their course and 
progress. 
The history of the reproductive function in the lower 
animals has, in fine, by constant accumulation of facts and 
theories, become now so voluminous that it is scarcely pos- 
sible, without long and close study, to form an adequate 
idea of the great research and intellectual effort expended 
on embryological investigations. Nor is it possible to con- 
dense within the limits of a short notice, such as the present, 
a tithe even of the numerous and interesting discoveries 
made during the last twenty-five years, or to attempt any- 
thing like a general outline of the various hypotheses and 
controversies which have arisen out of them. For our present 
