Cuar. XV.] THEIR POWER OF ABSORPTION. 285 
glands are formed of many cells, containing greenish matter with little 
globules of some substance. Leaves were left in an infusion of raw 
meat and in water for 26 hrs., but presented no difference. Some of 
these same leaves were then left tor above 2 hrs. in a solution of 
carbonate of ammonia, but no effect was produced. I regret that 
other experiments were not tried with more care, as M. Schloesing has 
shown* that tobacco plants supplied with the vapour of carbonate of 
ammonia yield on analysis a greater amount of nitrogen than other 
plants not thus treated ; and, from what we have seen, it is probable 
that some of the vapour may be absorbed by the glandular hairs. 
Summary of the Observations on Glandular Hairs—From 
the foregoing observations, few as they are, we see that the 
glands of two species of Saxifraga, of a Primula and Pelar- 
gonium, have the power of rapid absorption; whereas the 
glands of an Erica, Mirabilis, and Nicotiana, either have no 
such power, or the contents of the cells are not affected by 
the fluids employed, namely a solution of carbonate of 
ammonia and an infusion of raw meat. As the glands of 
the Mirabilis contain protoplasm, which did not become 
aggregated from exposure to the fluids just named, though 
the contents of the cells in the blade of the leaf were greatly 
affected by carbonate of ammonia, we may infer that they 
cannot absorb. We may further infer that the innumerable 
insects caught by this plant are of no more service to it 
than are those which adhere to the deciduous and sticky 
scales of the leaf-buds of the horse-chestnut. 
The most interesting case for us is that of the two species 
of Saxifraga, as this genus is distantly allied to Drosera. 
Their glands absorb matter from an infusion of raw meat, 
from solutions of the nitrate and carbonate of ammonia, and 
apparently from decayed insects. This was shown by the 
changed dull purple colour of the protoplasm within the cells 
of the glands, by its state of aggregation, and apparently by 
its more rapid spontaneous movements. ‘The aggregating 
process spreads from the glands down the pedicels of the 
hairs; and we may assume that any matter which is absorbed 
ultimately reaches the tissues of the plant. On the other 
hand, the process travels up the hairs whenever a surface 
is cut and exposed to a solution of the carbonate of ammonia. 
* «Comptes rendus, June 15, 1874. A good abstract of this paper is 
given in the ‘Gardener’s Chronicle,’ July 11, 1874, 
