OF CAMPANULA. 95 
explain their views of fecundation by reference to the process of 
graftmg, the cambium introduced by the pollen-tube becoming 
intimately blended with the cambium of the wéricule primordiale ; 
and according to the mode and degree of combination may be 
explained the formation of hybrids, some of which show the char- 
acter of the male parent, others of the female, and others a mixture 
of the characters of both the parents. 
The argument seems to depend upon the issue of the debated - 
question whether the primordial utricle has a prior existence within 
the ovule, independent of the action of the ovule. It will be 
advantageous to reject Schleiden’s figment of an introverted embryo- 
sac, and to substitute the simple idea of an embryonary cavity 
within the nucleus, prepared for the reception of an embryo. 
M. Ad. Brongniart contends that “in several plants, and particu- 
larly in the Cucurbitacee, he has ascertained that the vésicule 
embryonaire, considered by Schleiden to be formed of the extre- 
mity of the pollinic tube, exists in the ovule before fecundation.” I 
cannot confirm this statement as to the Cucurbitacee, where I find 
only an embryonary cavity, but no contained vesicle. In Zea Mays, 
an example prominently adduced by Mirbel and Spach in proof of 
their position, I find indeed the organ which they designate as the 
utrieule primordiale; but Y recognise in it only the quintine, analo- 
gous to that of Nuphar lutea, but not extending farther than the __ 
middle of the nucleus, and of peculiar confirmation. After repeated — — 
dissections, most carefully conducted, I am unable to detect the 
smallest trace of a suspensor like that figured by Mirbel and Spach — 
(Annales des Sciences Naturelles, April, 1839), and the “ grappe 
de très petites utricules ovoides qui couronnent l’utrieule primor- — 
diale” is not correctly represented in the plate, (fig. 11, 13, 15): — 
it consists of larger and fewer cellules, by no means pendulous, but 
forming a conglomerate opaque mass of an ovate oblong figure, 
which appears to be intimately connected with a central canal in 
the interior of the “ utricule primordiale," communicating with one 
or more roundish or oblong bodies (within the utricule) at the 
opposite extremity wherethe supposed suspensor should be visible, 
if it existed. The contents of the “utricule” [or quintine] cannot. 
be satisfactorily ascertained beyond this point, by reason. of th 
