doing comes
to a complete denial of Darwinism.

The other naturalist who has dealt Darwinism a telling blow is the
botanist of Graz, Professor Haberlandt.

He published some very interesting observations and experiments in the
"Festschrift fuer Schwendener" (Berlin 1899, Borntraeger). They are
concerned with a Liane javas of the family of mulberry plants
(Conocephalus ovatus.) The free leaves possess under the outer layer, a
tissue composed of large, thin-walled, water-storing cells; flat
cavities on the upper side, having, furthermore, organs that secrete
water, which the botanist calls hydathodes. These are delicate, small,
glandular cells over which are the bundles of vascular fibres
(leaf-veins) that convey the water to them; over these in the top layer
are so-called water-crevices through which the water can force itself
to the outside. It is unnecessary to enter upon a closer explanation of
the anatomical structure of these peculiar organs. The water which is
forced upward by the root-pressure of the plant is naturally conveyed
through the vascular fibres into the leaves and at every hydathode the
superfluous water oozes out in drops, a phenomenon which one can also
very nicely observe e.g. on the "Lady's cloak" (Alchemilla vulgaris) of
the German flora. A portion of the night-dew must be attributed to this
secretion of water. On the Liane, then, Haberlandt observed a very
considerable secretion of water: a full-grown leaf secreted during one
night 2.76 g. of water (that is 26 per cent. of its own weight.)
Through this peculiarity the water supply within the plant is regulated
and the danger avoided that any water should penetrate the surrounding
tissue in consequence of strong root-pressure,--which would naturally
obstruct the vital function of the entire leaf. Besides it is to be
noticed that in this way an abundant flow of water is produced: the
plant takes up large quantities of water from the earth, laden with
nutritive salts, and the distilled water is almost pure (it contains
only 0.045 g. salts), so that the nutritive salts are absorbed by the
plant.

From these considerations it necessarily appears that the hydathodes
are of great biological importance to the plant.

Haberlandt then "poisoned" the plant, by sprinkling it with a 0.1 per
cent sublimate solution of alcohol. The purpose of this experiment was
to ascertain whether in the secretion of water there was question of a
merely physical process