On the absorption of water by the green parts of plants. 
W. F. GANONG. 
Notwithstanding many experiments, the question as to 
whether land plants absorb any considerable quantities of 
water through their green parts is still unsettled. It is to be 
noticed that the two extremes of absorption, i. e., the ab- 
sorption of the major part of the water supply on the one 
hand, and of extremely minute and physiologically unimpot- 
tant portions on the other, are here not brought into discus- 
sion. The first is settled beyond all doubt in the negative, 
and the second is of comparatively little importance and ap- 
pears to be beyond any of the methods of investigation yet 
applied to it. But to know whether plants can under any 
normal conditions absorb water through green parts to am ex- 
tent sufficient to profitably supplement the root supply, is of 
much general interest, even though, as a side question upon 
which nothing of consequence depends, it is of no great Sth 
entific moment. 
The belief in the affirmative of the problem is very old and 
wide-spread, perhaps indeed nearly universal among garden- 
ers and others dealing in a practical way with living plants. 
Its principal basis is the familiar fact that plants drooping 
through loss of water by too rapid transpiration revive i 
sprayed in the ordinary fashion. But if the conditions of 
this spraying be controlled and varied by experiment, the re- 
lationship of cause and effect is found to be quite differen 
that which is apparent. If (as has incidentally happened 1? 
t from ? 
some of the experiments presently to be described) the watel 
be kept from the roots and the damp atmosphere create 
the spray be soon removed, the plant does not revive. ps 
g 3 
weight is found not to have increased, but rather dimin! 
as the following shows: 
the damp atmosphere be retained and the plant nite 
Exp. a. Healthy young Ricinus, the pot and earth wrapped in ere 
. hen weighed 3728". Placed in bell-jar moistened within, in twenty 
ours it had completely revived, but weighed 369.430 
Or again, if a plant be used which has wilted not 
too rapid transpiration, but through slower loss of 
throug! 
water 59 
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