'So it is also with the anastomosis of the vessels which spring forth from the larger veins, seeking each other with their ends and coalescing, and thus providing the necessary basis for the leaf-skin or cuticle. All this, if not entirely caused by subtle forms of air, is at least very much furthered by them. If the leaves of many water-plants are thread-like or assume the form of antlers, we are inclined to attribute it to lack of complete anastomosis. The growth of the water buttercup, Ranunculus aquatilis, shows this quite obviously, with its aquatic leaves consisting of mere thread-like veins, while in the leaves developed above water the anastomosis is complete and a connected plane is formed. Occasionally, indeed, in this plant, the transition may be still more definitely observed, in leaves which are half anastomosed and half thread-like.'