116 
Osborne, on the Wheat Plant. 
in which all such matter is suspended; that by another 
law_, a highly elastic vesicle is secreted external to a nucleus ; 
in its progressive expansion it forces its way, utterly indepen- 
dent of the other contents of the cell, into a layer of the 
plasm of which the cell-wall is constructed, until it has itself 
obtained the dimensions and general character of the cells 
of that particular portion of the vegetable structure to which 
it belongs ; that then the nucleus within it expands by the 
general separation of those particles of matter of which it is 
composed, until it has filled the space formed by the new cell 
which had been its matrix. The cell, now matured and 
occupied by the contents thus derived from the nucleus, 
absorbs some of them, and then, either by entire fresh secre- 
tion, or partly by that agency in combination with some por- 
tion of its original contents, a fresh nucleus is produced, to 
run the same course. 
That the epidermic plasm of these vegetable structures can 
secrete formative matter on its external surface, I have no 
doubt whatever, for I have again and again watched the pro- 
cess. I see no reason to doubt but that the plasm of the 
cell-walls has the same power with regard to its internal 
surfaces. On this power of external and internal secretion of 
tissues, which involve every portion of the organisms to which 
they belong, I think a sound theory is to be founded as to 
the whole process of vegetable cell -growth. 
Those who pursue this investigation will for ever find 
instances in which matured cells would seem to be isolated. 
I am satisfied that, in reality, this is never the case. They 
may be accidentally torn apart, or floating out from each other 
on or in the plasm in which they are produced, from its 
exceeding transparency they may appear to be separated, but 
when in situ with regard to the structure to which they 
belong, they are ever in connection either with the waUs of 
neighbouring cells or with those wonderful layers of elastic 
membrane whose evolutions and convolutions form a pro- 
tecting, secreting, absorbing, and assimilating surface, 
extending to every portion of the system of vegetable 
structure. 
I have now grown wheat plants rooted in spring water, 
distilled water, in a solution of alum, in spring water coloured 
with carmine, vermilion, and indigo. I have treated the 
water in which they were growing with various fertilising 
matters. I have grown them in thin layers of soil suspended 
over water, mixing with that soil various ingredients, and pig- 
ments, and bronze powder. I have now plants, with a foliage 
of fourteen inches, growing in a strong solution of prussic acid 
