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How is this mode of reproduction to be explained? is a question 
that has troubled naturalists from the days of Bonnet, who first dis¬ 
covered it, down to the present time. Leuwenhock and Cestoni were 
of the opinion that the supposed agamic females were in fact herma¬ 
phrodites. Morren, a professor of the University of Liege, after a 
careful anatomical examination, apparently set this theory at rest. It 
was his opinion—a view adopted by the celebrated Owen—that all i 
these changes are brought about by some force concentrated in the 
sperm cells, or, as the latter has in substance expressed it, the sper¬ 
matic force is transmitted to a mass of germ cells, and these germ 
cells are the direct excitants of all the changes in the successive 
generations of cells, until the impregnation of the next ovum. On 
this theory, the germ stock—for “force,” as here used, can mean 
nothing else—would soon be exhausted, and the reproduction limited. 
It also requires the transmission of a part of the original germ stock 
through, sometimes, as many as twenty generations, and with a possible i 
division, according to Owen himself, among more than a million times 
a hundred million descendants. 
Another serious objection to this theory is the evidence furnished by 
Kyber’s experiment, in which he kept up viviparious generation for 
four years, at the end of which the agamic females appeared to have 
the same power of reproduction as the first brood. I do not fully and; 
clearly understand Huxley’s theory, but the chief idea appears to be 
that of germination or budding, somewhat similar to that observed in 
some of the Polvpe. But his explanation of the production oi the 
ovum in the fall is scarcely satisfactory. Dr. Burnett, according to 
Packard, also considers this "mode of generation a process of budding 
similar to that seen in vegetables, and that the whole series, from the 
spring egg until the end of the last fall brood, is but a single genera¬ 
tion resulting from the union which produced the egg in the fall, just 
as the leaves of the tree, which are renewed each year, are said to be 
contained in the germ of the acorn, or to result from the union of 
the staminate and pestillate elements that produced the acorn. I he 
theory is the same as Huxley’s in substance; but the illustration is 
wholly inapplicable, as the leaves are but the organs of the individual, 
as are the legs and antennae of each individual Aphis. 
Parthenogenesis and Agamogenesis are terms which, upon their face,| 
are indicative of our ignorance of their meaning, and are used to ex¬ 
press a fact without conveying an idea, if we can suppose such a 
thing possible. Balbiani has revived the old theory of Leuwenhocp 
and Cestoni, that of internal impregnation or hermaphrodism. H e 
maintains that the embryo viviparous Aphidians are hermaphrodites.] 
He also finds a similar condition in other species considered parthe ( 
nogenetic, thus striking a heavy blow at this incomprehensible theory: 
There are numerous facts in the life-history of some of the lower 
animals, as strange as it would be for the male principle to be retained] 
under certain circumstances in the female Aphis, and separated under 
others. This is the simplest explanation that can be found, and it 
will explain how it is possible to protract indefinitely the agamh 
reproduction. 
But it is not necessary for me to discuss this question further here 
for although very interesting to the physiologist and naturalist, it ha: 
