2 MR. 8. G. SHATTOCK ON THE REPARATIVE 
cells are so arranged as to form a compact leaf-like parenchyma. 
The repair in all such simple cellular or parenchymatous plants, 
with perhaps very rare exceptions, is effected by disintegration of 
the cells spoiled and the unmodified growth of the parts imme- 
diately beneath. Frank* quotes from Hanstein a proper cell- ` 
repair as occurring in Vaucheria, the divided protoplasm of the 
thallus producing a cellulose partition continuous with the original 
wall, and the thallus subsequently growing out by the side of this 
terminal partition. ` 
When it is eonsidered, however, that the protoplasm in Vau- 
cheria is polynucleated, this apparent exception is rendered 
perhaps conformable to rule; and I may proceed at once to con- 
sider the reparative processes as they occur in the higher plants. 
And as the tissues of these differ in no essential respects, I shall 
limit myself to phanerogamous plants, and even further, chiefly 
to those which are exogenous. 
The subject of repair may be considered. as it oceurs, first, 
after amputation ; secondly, after incision; and, thirdly, as it 
occurs in the artificial union of parts in grafting and budding. 
And under each of these headings the process may be noted, so far 
as necessary, as it proceeds in the stem, in the leaves, or in the root. 
First, then, in regard to amputation. Ifthe growing peduncle 
of the Hyacinth ( Hyacinthus orientalis, Linn.), be half cut across, 
the growth of the parts proceeds without manifest interruption, 
and the divided surfaces appear at the termination of growth 
scarcely altered. A longitudinal section, when placed beneath 
the microscope, displays the divided cells scarcely displaced, 
empty, yet preserving their form, and still bounding the chief 
part of the surface. The cells beneath those spoiled are rounded 
at those ends which are towards the wound, whilst their oppo- 
site ends are flat and adapted to the flattened ends of the 
adjoining elongated cells, as the ends of these cells are adapted to 
one another. Besides this, the ends of some of the entire cells 
may be found enlarged, bulbous, or clavate ; and some may have 
pushed bud-like processes from the sides of their enlarged ex- 
tremities. The changes apply equally to the medulla and to the 
cortical parenchyma. The divided fibro-vascular bundles are 
overlapped by the overgrown bulbous and divided cells t 
* “Die Krankheiten der Pflanzen,’ p. 97. 
T Frank notices a similar mode of repair from the mesophyll in the leaves of 
Leucojum vernum. 
