254 Scott and Sargant. — On the Pitchers of 
almost at right angles to the axis of the organ ; the part just 
behind the apex was already slightly hooded. The pitcher 
was cut, by means of the Cambridge rocking-microtome, into 
a series of transverse sections. The whole course of the 
vascular bundles in the young pitcher was thus completely 
disclosed, but it would be superfluous to enter into any full 
description, as the structure is in all respects that of a typical 
Dicotyledonous leaf of the 5 isobilateral ’ type. There was no 
strictly apical growth at this stage ; the morphological apex 
was surmounted by a gland, to which we shall return. The 
growth was most active in the hooded part just behind the 
apex, and here the tissues showed the least differentiation. 
Another pitcher, which with its petiole was about f in. 
(i cm.) long, was microtomed in the longitudinal direction, 
parallel to the plane of symmetry. At this stage there is no 
definite localization of growth. The whole curved part of the 
organ seems to be actively developing, the mesophyll-cells 
showing indications of recent transverse divisions. Only at the 
base and apex growth appears to have ceased. At this stage 
the pitcher has attained its definitive form. Up to this time 
the histological structure of the pitcher is just that of a young 
foliage-leaf ; the differentiation of the mesophyll, described 
above, only takes place at a later stage. 
These serial sections, showing the whole structure of the 
pitcher at the stages in question, were prepared with the special 
object of determining whether any glandular organs are present, 
which might have been overlooked by previous observers. 
The careful examination of mature pitchers, in hand-sections, 
indicated nothing of the kind, but the only way of proving 
a negative was to examine the whole organ throughout, and 
this is just what the series of microtome-sections enabled us 
to do. The pitchers examined in this way were of necessity 
young ones. In the pitcher § in. long however all the 
definitive tissues were present; the mesophyll had attained 
its full thickness, and many of the stomata were almost fully 
developed. No signs whatever of any developing glands were 
present on any part of the pitcher. 
