154 DEVELOPMENT OF THE OVULUM 
it accords well with what he says of its never being visi- 
ble before the period of fecundation. 
I have no doubt but that subsequent examination will 
prove it to be of the nature alluded to. 
But I doubt much whether such very distinct communica- 
tions will be seen as are represented in his excellent figures, 
in which the openings in the tubes, are obviously made to 
conform to his peculiar theory. 
Even if it were proved that such tubes are not the remains 
of the boyaux, analogy would lead us to conclude that they 
are extensions of the embryonary sac, such extension being 
a more direct method of accounting for them than that un- 
der examination. 
To this, however, there is an objection which I consider 
fatal, viz. that as the embryo is always developed at the apex 
of the embryonary sac, in all such cases it would necessarily 
be developed externally to the ovulum, of this an instance 
actually occurs in Santalum. 
I am aware that Mirbel considers the embryo of some 
Leguminosz, as for instance Pisum sativum, to be formed at a 
considerable distance from the apex of the embryonary sac; 
ut doubts must always be attached to the observed site of 
such a minute body, when sections are resorted to. And in 
the figure 19, pl. 9, I would beg to remark that the radicle 
of the young ovulum points to the geometric, not the real 
apex of the seed, a site totally contrary to all analogy. 
Arguing on the supposed existence of communication, 
M. Brongniart considers that a period of 8 days at least 
would be sufficient to ensure impregnation. If my idea how- 
ever be correct, fecundation had been already completed. I 
shall return to this subject however, when speaking of the 
performance of this function. 
M. Mirbel's account of the nucleus and, I may add, of all 
the remaining formations is materially different. This 
distinguished botanist states, that in certain orders, as most 
guminose, and above all in Labiate, Boraginex, the 
ovulum must be examined at a very early period to enable 
one to ascertain the existence of the nucleus, owing to 
