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REVIEWS. 
On a True Parthenogenesis in Moths and Bees, a contribution 
to the history of Reproduction in Animals. By Carl 
Theodor Ernst von Siebold. Translated by William 
S. Dallas^ F.L.S. London^ Van Voorst. 
The whole theory of reproduction, as it occurs in plants 
and animals, has undergone curious and interesting changes, 
according as new observations have been made from time to 
time. Amongst the earlier naturalists sex was only recog- 
nised amongst the higher animals, and the lower animals and 
plants were supposed to be produced by a process of budding. 
Gradually, however, it became evident that amongst the 
lower animals sexes existed, and at length the discovery was 
made of the true relations of the pollen of plants to the ovules 
contained in the pistil. Then followed the sexual system of 
Linnseus. But Linnaeus was not aware how far the an- 
tagonistic cells existed amongst the lower plants, and it has 
been the discovery of microscopists of recent times that 
sperm-cells and germ-cells exist in the Linnean Crypto- 
gamia. So far have these discoveries been extended in both 
the animal and vegetable kingdom, that it would appear to 
be a general law that no true species of animal or plant is 
renewed without the union of sperm-cells and germ-cells. 
But whilst these observations were going on, many curious 
instances of anomalous production of individuals were ob- 
served. Steenstrup drew attention to the fact that many 
animals, whilst passing from their youngest to their adult 
forms, produced new individuals without any union of germ- 
cells and sperm-cells. Such animal forms he called nurses.^' 
Professor Owen observed the phenomenon of " nursing" with 
great care in the well-known plantlouse [Aphis) . In these 
creatures, the young, generated by the union of the sperm- 
cell and the germ-cell, produce young, resembling them- 
selves, for eight or nine generations without any union of the 
two opposite cells. This Professor Owen calls Parthenogenesis. 
In the work of Professor Von Siebold, translated by Mr. 
DaUas, we have an account of the production of bees and 
moths from eggs which have been produced independent of 
any contact of the sperm- cells with the germ- cells. To this 
process of genesis, in which eggs, capable of producing the 
perfect form of the parent, Von Siebold proposes to apply 
