of Hippuris vulgaris. 265 
served after animal impregnation is the development of two 
cells in the germ-vesicle. These cells then multiply to a greater 
or less extent by transverse division so as to form a confervoid 
filament. At last, either at the centre or termination of this fila- 
ment, one cell becomes developed by an endogenous mode of cell- 
production into a body to which the term embryo-globule is 
applied, and which is in fact the future embryo, while the rest 
perform a subordinate function, being probably merely subser- 
vient to the nutrition of the embryo. This last process corre- 
sponds in animals to the successive divisions of the two cells 
previously referred to, what is called the “cleaving of the yelk 
mass,” on the surface of which the embryo is subsequently de- 
veloped. 
The foregoing sketch of what may be considered as the morpho- 
logical type of the embryogenic development in the higher plants 
will, it is believed, include all those modifications which occur in 
those families which have been hitherto investigated. And consi- 
dering that of late years, since the means of research have been so 
much more complete than formerly, there has been such a remark- 
able consonance in the results obtained by different observers, 
there is little reason to apprehend that any new facts are likely to 
arise, which will render it necessary to modify our generalizations 
to any great degree. We may therefore consider the controversy 
for the present settled. The doctrine of Schleiden is now only 
a matter of history, and as such possesses very great interest. 
When in 1837 he first brought forward his splendid discoveries 
as to the previously unknown nature and functions of cells, he 
founded upon them another doctrine, according to which the 
existence of sexes in plants was denied, and the so-called male 
organ alone was supposed to origimate the germ. The history 
of this celebrated doctrme exemplifies in a remarkable manner 
the truth of the observation, that, although false facts may do 
an infinity of mischief in science, false theories are often produc- 
tive of the greatest benefit. 
The numerous researches which have been set on foot within 
the last ten years with a view to the refutation of the doctrines 
of Schleiden, have not only established the utter baselessness of 
these last, but have furnished us with a series of details more 
complete and more conclusive than any which we possess in con- 
nection with any other subject in the whole range of vegetable 
anatomy. 
