Miscellaneous. 497 
On the Motory Phenomena caf Animal Cells. 
By N. LigszgküEN 
M. Lieberkühn's memoir contains numerous observations upon 
the obscure phenomena of intracellular life. It is difficult to arrange 
them in a single whole, although they relate without exception to a 
common subject. e following is a sketch of the principal facts. — 
Schwann had already been struck by the resemblance of the tissue 
of the chorda dorsalis to that of vegetable cells. "This comparison 
has since been confirmed. The fund amental chondrogenous sub- 
of changes of form are often stretched. The nuclei are applied 
against the wall. At a later period of development the granular 
protoplasm disappears, and there smi uud a frothy substance, 
whieh at last disappears in its turn. Some very small granules 
which are sometimes found in the saltus liquid show 7 their mo- 
lecular movement that they are situated in a very medium ; 
. and their movement of progression proves the existence bof determi- 
id. 
nate currents in this 
arge portion of M. Lieberkühn's researches bear upon the rela- 
as to give origin to a sort of v in which small vacuoles may 
unite to form larger ones. Sometimes we even find one large va- 
cuole in each cell. In this case ere contain a transparent liquid, 
and the nucleus is always placed in the protoplasm surrounding it 
its turn disappear completely ; or only a few small vacuoles may re- 
main in the protoplasm of the cell, and then these vacuoles suddenly 
contract like the contractile vesicles of the Infusoria. Notwith- 
Standing assertions to the contrary, M. Lieberkühn maintains the 
opinion that the contractile substance of the Spongille is formed 
entirely by the aggregation of independent cells; this he demon- 
strates by bringing a Spongilla to a temperature of about 140° F. 
The cells are then seen to contract and separate from each other in 
isolated masses, each furnished with a nucleus. The cells of 
Spongilla, like the tissue of the chorda dorsal, are able, in certain 
cases, to reproduce the plan of vegetable cells. "This is what occurs 
during the formation of the siliceous parts of the Bicis of Es. 
gemmules. Thus, at the surface of the soft protoplasm of the c 
his 
becomes atrophied. It is certain that the vacuoles of the cells of 
Spongilla are filled with a liquid of very small density; for the gra- 
Ann. & Mag. N. Hist. Ser. 4. Vol. vi 34 
