Onar. XV, THEIR POWER OF ABSORPTION. 353 
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 Pelargonium, 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 am- 
monia 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 appa- 
rently by its more rapid spontaneous movements. 
* «Comptes rendus,’ June 15, 1874. A good abstract of this paper 
4s given in the ‘Gardener’s Chronicle,’ July 11, 1874. 
