ISY D. MCALPl>fE. 617 



flower, including the carpels, is fully supplied with vascular 

 bundles. 



Vascular Bundles as a whole. 



It is not always practicable to get a complete and connected 

 view of the vascular system of any particular organ, so as to 

 understand how it is strengthened, and how it is nourished, 

 how the delicate cells composing it are prevented from collapsing, 

 and how the nutritive juices are conveyed to and from each 

 part. 



In the case of "skeleton" leaves, or leaves which have been 

 bleached, the course of the vascular bundles may be easily 

 followed. In net-veined leaves, such as those of the apple 

 (Fig. 18), all the vascular bundles entering them are gathered 

 into the midrib, and branches spread thence to all ])arts of 

 the leaf. The branches or veins divide and subdivide until 

 the meshes are exceedingly small, and the ultimate veinlets 

 end free in the substance of the leaf. Every part of the leaf 

 is traversed by this network of channels, and, at the same 

 time, efficiently strengthened. But while flattened leaves 

 may be readily bleached or even naturally skeletonised, 1 

 have never found a pulpy fruit, such as the apple, with the 

 flesh decayed, and showing the complete framework natur- 

 ally. I have succeeded, however, in separating out the 

 bundles by artificial means. A healthy and mature Five- 

 Crown apple was placed in a weak solution of potassium 

 hydrate for a week, during which time the soft pulpy material 

 was gradually removed, until, at the end of the week, the 

 strands stood out quite distinct. It was next laid out in 

 water, and, with brush and needle, the remaining soft parts 

 were detached, so that ultimately there remained the ten 

 strands with their ramifications, as photographed .(Fig. 8). 

 One would hardly imagine that a tender, juicy apple con- 

 tained such a network of filaments, but without them the 

 apple could never have grown to its full size, nor acquired its 

 succulence and flavour. How this is so, will now be briefly 

 indicated. 



