510 
W. J. V. OSTERHOUT 
flourish. In view of this it seemed desirable to ascertain how much 
moisture they could endure. For this purpose pieces eighteen inches 
in length were fastened at one end and anchored in a small, rapidly 
running brook during the month of August. The temperature of the 
water varied from 20° to 25°C. 
Care was taken to keep all the pieces constantly submerged but not 
to let them sink more than an inch below the surface. The proximity 
to the surface and the motion of the water (which was aerated by a 
small waterfall directly above) ensured a fair supply of oxygen. Under 
these circumstances the plants grew a little (the average growth was 
one tenth of an inch during the month) but no new leaves were formed 
and all the leaves except some of the very youngest became pale and 
yellowish in color. The tips of some of the plants were still alive when 
the experiment was discontinued. Undoubtedly the plants would have 
done still better if it had been possible to supply more oxygen to them. 
It is therefore evident that the same individual could live for 
nearly two years without water and afterward grow vigorously in a 
saturated atmosphere ; in addition, it could live for a month under water 
and grow a little during that time. 
The writer has had occasion to study other cases^ which can not be 
explained by gradual adaptation. It would seem that in these cases 
the explanation must be sought in physical and chemical peculiarities 
of protoplasm which arise without reference to adaptation. It is 
quite possible that this kind of explanation should find more extensive 
application and that many cases now regarded as adaptations may 
prove to be fictitious. 
Summary 
A species of Tradescantia lived for nearly two years without soil 
or water: it afterward grew vigorously in a saturated atmosphere and 
was finally placed under water for a month, during which time it grew 
slightly and was alive at the end of the experiment. 
The explanation of such cases must be sought in physical or chemi- 
cal conditions of the protoplasm which arise without reference to 
direct adaptation. It would seem that the same kind of explanation 
may apply to many cases which are now regarded as adaptations. 
Harvard University, 
Laboratory of Plant Physiology 
2 Cf. Osterhout, W. J. V. Univ. Calif. Publ. Bot. 2: 227. 1906. Bot. Gaz. 
55: 446. 1913. 
