140 DEVELOPMENT OF THE OVULUM 
removed partly by the supposition of openings, existing in 
the tubes! 
The same hypothesis has led to the statement that at least 
8 days are sufficient to allow of the completion of the passage 
in Cucurbita, to this I have elsewhere alluded, and to the sup- 
position that months are required in Corylus for the comple- 
tion of the same passage. Mr. Brongniart considers in this 
case, that the impregnating fluid either remains stationary in 
some part of the plant, or that more probably the embryo 
after its first development remains in a torpid state. I have 
elsewhere mentioned that a discrepancy exists between 
Mirbel and Brongniart as to the degree of development of 
the ovula of Corylus. I may observe that even if Br's. state- 
ment be correct* 
his more probable idea is contrary to all analogy, otherwise, 
there may legitimately be inferred to exist, no confined limits 
to the growth of a body endowed with a special vitality, as 
the pollen boyau no doubt is. 
The completion of the discovery is due to Mr. Brown, 
to whose paper I refer. The fact is now admitted on all 
sides within the scope of my experience. 
Within the scope of my experience, limited as it necessa- 
rily must be, there is no modification which destroys the pos- 
sibility of the direct communication of the tubes with the 
ovula. But it must be remembered that Mr. Brown, the 
first authority in this, as in all other points connected with 
vegetables, remarks that it does not follow that descent and 
insertion of the tubes should be expected to extend to all 
Pheenogamous plants ; for among these some structures of the 
female organ exists, which hardly admits of this economy. 
See Suppl. Obs. on sexual organs and impregnation in 
Orchid. and Asclepiad. p. 4. 
* The consecutive order of the MS. not having been marked by the author, 
breaks, corresponding with the MS. pages, are left in the type 
