Absorption of Water by some Succulents. 
399 
Experiments with Eosine Solution. 
On the 23/5 freshly cut branches of Mescmbrianthemum barbatum and 
Anacampseros filamentosa were dipped in a strong, watery solution of 
eosine and left in the solution for twenty-four hours. In the first the 
stellate hairs were stained, everything else was unstained. This was 
confirmed by microscopic examination. In Anacamjyseros the long hairs 
were stained, everything else looked normal. Microscopical examination 
showed that no eosine had penetrated into stem or leaves. On the 
24/5 branches of all three kinds of plants experimented with were cut 
and left dry in the laboratory. The cut ends were not sealed in this case. 
All except Anacampseros showed external signs of withering on the 29/5 ; 
on that date their upper portions were dipped in eosine solution and left 
for twenty-four hours, after which they were examined. The result was 
as follows : — 
Anacampseros : Hairs distinctly stained, otherwise no sign of red, 
either externally or internally. 
Mescmbrianthemum : Except stellate hairs, no part showed either 
externally or internally any signs of red. 
Grassula : Papillae faintly stained, vascular bundles in leaves and 
stem distinctly red, nothing else stained. 
Thus this test only showed penetration of watery eosine solution in 
Grassula cymosa after the branches had been kept dry for nearly a week 
with the cut ends not sealed. 
It seemed desirable, therefore, to determine in the first place whether 
the gain previously mentioned in Anacampseros after immersion in water 
for five hours was due to the fact that the water was sucked up by the 
hairs as by a sponge or whether the leaves themselves had absorbed it. 
The same two branches were therefore again weighed on the 30/5, and it 
was found that while the one that had on the previous day been soaked 
for five hours had lost 8-3 per cent, of its weight the other, which had 
only been dipped for fifteen minutes, lost only 4-4 per cent, of its weight. 
They were then both immersed for twenty-five minutes in eosine solution 
and then weighed after having been dried as carefully as possible with 
blotting-paper. The former then showed actually a small gain on the 
previous day's weight; it weighed 9*164 gr., while the latter weighed 
5-044 gr., which was a little less than the day before. However, no sign 
of red could be found in the interior of the plant, and this, in conjunction 
with the other facts mentioned, seems to show pretty conclusively that, 
as in Mesembrianthemmn barbatuvi, no appreciable quantity of liquid water 
can enter the aerial organs from without. The gain in Anacampseros was 
evidently due to the absorption of water by the long, dead hairs and not 
by the leaves themselves. This gain is readily acquired, but also readily 
