matter, or secrete an odoriferous fluid as a protection against the attacks of insects, or for any other purpose, and yet have the power of absorbing.  I regret that in the following cases I did not try whether the secretion could digest or render soluble animal substances, but such experiments would have been difficult on account of the small size of the glands and the small amount of secretion.  We shall see in the next chapter that the secretion from the glandular hairs of Pinguicula certainly dissolves animal matter.

[Saxifraga umbrosa.—­The flower-peduncles and petioles of the leaves are clothed with short hairs, bearing pink-coloured glands, formed of several polygonal cells, with their pedicels divided by partitions into distinct cells, which are generally colourless, but sometimes pink.  The glands secrete a yellowish viscid fluid, by

The distinction between true absorption and mere permeation, or imbibition, is by no means clearly understood:  see Mller’s ‘Physiology,’ Eng. translat. 1838, vol. i. p. 280. [page 346]

which minute Diptera are sometimes, though not often, caught.* The cells of the glands contain bright pink fluid, charged with granules or with globular masses of pinkish pulpy matter.  This matter must be protoplasm, for it is seen to undergo slow but incessant changes of form if a gland be placed in a drop of water and examined.  Similar movements were observed after glands had been immersed in water for 1, 3, 5, 18, and 27 hrs.  Even after this latter period the glands retained their bright pink colour; and the protoplasm within their cells did not appear to have become more aggregated.  The continually changing forms of the little masses of protoplasm are not due to the absorption of water, as they were seen in glands kept dry.

A flower-stem, still attached to a plant, was bent (May 29) so as to remain immersed for 23 hrs. 30 m. in a strong infusion of raw meat.  The colour of the contents of the glands was slightly changed, being now of a duller and more purple tint than before.  The contents also appeared more aggregated, for the spaces between the little masses of protoplasm were wider; but this latter result did not follow in some other and similar experiments.  The masses seemed to change their forms more rapidly than did those in water; so that the cells had a different appearance every four or five minutes.  Elongated masses became in the course of one or two minutes spherical; and spherical ones drew themselves out and united with others.  Minute masses rapidly increased in size, and three distinct ones were seen to unite.  The movements were, in short, exactly like those described in the case of Drosera.  The cells of the pedicels were not affected by the infusion; nor were they in the following experiment.

Another flower-stem was placed in the same manner and for the same length of time in a solution of one part of nitrate of ammonia to 146 of water (or 3 grs. to 1 oz.), and the glands were discoloured in exactly the same manner as by the infusion of raw meat.