30 MEYEN OW VEGETABLE IMPREGNATION 
in the berries of this plant. The contents of these cells also, 
which at first consisted of small globules, and of a larger ball of 
a gummy substance, is dissolved and changed into viscin. In 
this visciniferous layer is situated the lenticularly compressed 
nucleus cc ; it was in the young flower perfectly round, solid, and 
without any envelope ; subsequently a cavity was formed in it for 
the formation of the embryo-sac, and it then expanded laterally, 
while the inner still persistent cellular tissue became very wide- 
meshed, so that even with a power of twenty these cells are 
very easily recognised. Lastly, the albuminous body with the 
embryo expands to such an extent that the entire inner cellular 
mass of the nucleus is dislodged, and only a few layers of cells still 
remain, of which the outer ones exhibit very large and beautiful 
spiral fibrous cells. In fig. 5. ¢ represents the embryo-sac, with 
the albumen situated within the cavity of the nucleus, and sur- 
rounded on all sides with a mucous mass, and large latticed 
delicate cellular tissue. The embryo exhibits until nearly its 
complete development, a small funiculus, which, however, gene- 
rally consists of a single cell. 
What is most remarkable in the formation of the albuminous 
body of Viscum, is the previous division of the embryo-sac into 
large cells, a phenomenon which, however, is no longer so iso- 
lated. M. Brongniart, in his celebrated memoir on the produc- 
tion of the vegetable embryo, already gave a representation of 
the embryo-sac of Ceratophyllum submersum, according to which 
it consists of three large cells arranged near each other; but he 
had not then observed that these cells result by constriction 
from the previously quite simple embryo-sac. M. Horkel at 
that time pronounced the cellular embryo-sac, according to 
Brongniart’s drawing, to be large-celled albumen, and M.Schlei- 
den supposed he had proved this*, by representing around it a 
distinct embryo-sac, of the non-existence of which I think I 
have perfectly convinced myself. But this is not exactly the 
place to enter into more minute detail on the formation of the 
large-celled embryo-sac of Ceratophyllum; the formation of the 
albuminous body in it differs, however, from that of Viscum in 
this only, that in the latter all the large cells of the embryo-sac 
gradually fill from above downwards with the albuminous body; 
while in Ceratophyllum it is only formed in the three upper 
large cells, and the other still larger cells shrivel together as 
* Linnea, vol. xi. fig. 9. 
