148 Vaizey. — On the Absorption 
almost immediately caught my attention, namely, that 
whether in the wild state or under cultivation changes in 
the dampness of the air affected the oophyte much more 
rapidly than the sporophyte ; so much so, that on quite hot 
dry summer days, when the leaves of the oophyte of Mosses, 
which were in fruit, were quite withered and rolled up with 
the drought, the sporogonium was quite fresh and did not 
wither unless the drought was excessive. It was, in fact, 
only very rarely, even in the past exceptionally dry summer, 
that I found the sporogonia of Mosses (that is, of course, 
those which had not dried up after maturation of spores) 
appreciably affected by the want of water. This observation 
and the rapidity with which the leaves of Mosses recover 
from the dried-up condition after a little rain or dew has 
fallen or formed upon them, suggested certain experiments. 
I obtained stems of P oly trichum commune , L., some 15-20 
cm. in length, which I placed with their cut ends in water, 
about half-an-inch being below the surface. Placed in a 
cool room with a dry atmosphere, in less than half-an-hour 
all the leaves, except the last half-dozen nearest the water, 
were withered. Some stems of P. formosum , Hedw., with 
their cut ends in a solution of eosin in water, were placed, 
some in an atmosphere just so damp that the leaves did 
not wither, others in a drier atmosphere so that the leaves 
withered slowly. In neither case did the eosin pass more 
than a few millimetres up the stem, about far enough to 
be accounted for by diffusion. If, on the other hand, water 
was placed on the leaves, or if one of the stems was dipped 
growing point foremost into water, the cut end being carefully 
kept dry, the leaves rapidly recovered. If, instead, the cut end 
of the stem was dipped into a solution of eosin in water, the 
leaves and tissues of the stem were found to be full of the 
solution. It then became clear that water can be absorbed 
by the leaves of the Moss, and consequently can pass through 
the external cell-walls of the leaf. 
The subject of observation then became the constitution 
of the cell- walls of the leaves and stems of the oophyte 
