404 Farmer. — On the Morphology and 
the latter might be of the nature of a secretion, which spreads 
over the free portions of the cell-walls which line the inter- 
cellular spaces. Reference, however, to Crataegus and other 
similar forms shows that this point has but little weight, and 
besides this, it is not likely that cells engaged in rapidly 
dividing would be also employed at the same time in actively 
secreting mucilage. Thus, although the actual steps resulting 
in its formation are difficult to follow, there can remain but little 
room for doubt that the substance in question owes its origin to 
degenerative changes which are going on in the outer layers of 
the cell-walls, and which only become evident at a period sub- 
sequent to the splitting apart of the cells, which results in the 
formation of the intercellular spaces referred to. And indeed 
it has already been pointed out that the cells of the interior of 
the fruit are obliged to split, in order to admit of the radial 
extension of the whole, since the peripheral cells divide, at 
first, in such a way as necessitates either such an expansion, or 
a throwing of the surface into folds, and in this way it is 
possible that the result may become manifest before the cause 
which effected it. 
Whilst the mucilage is apparent at an early period it 
becomes far more pronounced as the time of maturity draws 
near. The number of cells of which the pulp is composed is 
at this time very large, but the riband-like arrangement is 
still easily discernible, especially near the periphery ; in con- 
sequence, however, of the increase in the absolute size of the 
cells in the internal part of the fruit, the bands become 
forced into close juxtaposition, and the intercellular spaces 
form a proportionately smaller part of the entire volume 
of the fruit. Hence in sections taken through mature speci- 
mens the process of swelling can be readily followed out, as 
the addition of water to the preparation effects a great 
displacement of the cell-ribands, which were originally almost 
in contact. 
The cell-contents do not present any features of striking 
interest as long as the fruit continues to grow in size. Chloro- 
phyll is present, especially in the peripheral layers of cells, and 
