consequence of a very definite force inherent in the mineral-substances;
nor will any one deny the existence of the force of crystallization
because it does not appear in living organisms.

Nor have I ever despaired of a return of the theory of vital force. A
change of opinion has really taken place during this decade; at present
the voices for a vital force are constantly growing stronger and it
will most probably not be very long before it will be again universally
recognized, not as something preternatural, of course, but as a force
of nature on an equal footing with the other forces of nature, with
activities, just as mysterious and just as well-attested as the
activities of the other forces of nature.

Haberlandt's experiment, however, had also an indirect consequence that
is of far-reaching importance. He observed that within a few days new
water-secreting organs of an entirely different structure and of
different origin were formed on the leaves that had been sprinkled with
sublimate. Over the bundles of vascular fibres, little knots as large
as a pin head arose in larger numbers out of a tissue underlying the
top layer; out of these the water now oozed every morning. Closer
investigation disclosed the fact that these organs develop only on
young immature leaves where groups of peculiar, perishable gland-hairs
are found; beneath these dead mucous glands the substitute secretive
organs originate in the inner tissue. It is of no importance to state
in what particular cells they originate.

Suffice it to say that they are colorless capillary tubes originating
in various cells; projecting like the hairs of a brush, containing
living protoplasm and evanescent chlorophyll. It is also important
to note that this new organ is immediately connected with the
water-conducting system consisting of bundles of vascular fibres.
Haberlandt furthermore indicates especially that these organs when
viewed in connection with the process of secretion give evidence of an
active vital principle as well as of simple mechanical filtration.

These substitute organs are all indeed well adapted to their purpose
and adequately replace the old secretive organs, but they so easily dry
out and are so little protected that after a week they become parched
and die because wound-cork forms under them. The leaf no longer
produces new hydathodes, but on its lower side it produces growths that
function as vesicles, by means of which it continues to