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Show 348 GLANDULAR HAIRS, CHAP. XY. difference from the glands of other hairs. Perhaps there may not have been time enough for absorption. I think so as some glands, on which dead flies had evidently long lain, were of a pale dirty purple colour or even almost colourless, and the granular matter within them presented an unusual and somewhat peculiar appearance. That these glands had absorbed animal matter from the flies, probably by exosmose into the viscid secretion, we may infer, not only from their changed colour, but because, when placed in a solution of carbonate of ammonia, some of the cells in thdr pedicels become filled with granular matter; whereas the cells of other hairs, which had not caught flies, after being treated with the same solution for the same length of time, contained only a small quantity of granular matter. But more evidence is necessary before we fully admit that the glands of this saxifrage can absorb, even with ample time allowed, animal matter from the minute insects which they occasionally and accidentally capture. Saxijrr_tga rotwtd,foha (?).-The hairs on the flower-stems of this species are longer than those just described, and bear pale brown glands. Many were examined, and the cells of tho pedicels were quite transparent. A bent stem was immersed for 30m. in a solution of one part of carbonate of ammonia to 109 of water, and two or three of tho uppermost cells in the pedicels now contained granular or aggregated matter; the glands having become of a bright yellowish-green. The glands of this species therefore absorb the carbonate much more quickly than do those of Saxifraga urnbrosa, and the upper cells of the pedicels are likewise affected much more quickly. Pieces of the stem were cut off and immersed in the same solution; and now the process of aggregation trave1led up tho hairs in a reversed direction; the cells close to the cut surfaces being first affected. Primula sinensis.-The flower-stems, the upper and lower surfaces of the leaves and their footstalks, arc all clothed with a multitude of longer and shorter hairs. The pedicels of the longer hairs are divided by transverse partitions into eight or nine cells. The enlarged terminal cell is globular, forming a gland which secretes a variable amount of thick, slightly viscid, not acid, brownish-yellow matter. A piece of a young flower-stem was first immersed in distilled 'water for 2 hrs. 00 m., and the glandular hairs were not at all affected. Another piece, bearing twenty-five short and nine long hairs, was carefully examined. The glands of the latter contained no solid or semi-solid matter; and those of only two CHAP. xv. THEIR POWER OF ABSORPTION. 349 of the twenty-five short hairs cont~ined som~ globules. This ieee was then immersed for 2 hrs. In a solutwn of one part of p b ate of ammonia to 109 of water, and now the glands of tchaer towne nty-five shorter hairs, wi. th two or thr ee excep t'w ns, c?n-tained either one large or from two to five smaller s:phencal masses of semi-solid matte: .. Three of the glands of the :r;nne long h:e 1·: es likewise included s1m1lar masses. In a few hairs there also globules in tho cell~ immediately beneath the glands. Looking to all thirty-four hairs, there could be no doubt ~hat the glands had absorbed some of the carbonate. Another pwce was left for only 1 hr. in the same solution, and. aggreg~ted matter appeared in all the glands. My son Francis examrned some glands of the longer hai~·s, which c?ntained litt~e ma~ses of matter, before they wore Immersed In any solutiOn; and these masses slowly changed their forms, so that no doubt they consisted of protoplasm. He then irrigated these hairs for 1 hr. 15m., whilst under the microscope, with a solution of one part of the carbonate to 218 of water ; the glands were not perceptibly affected nor could this have been expected, as their contents were already 'aggregated. But in the cells of the pedicel~ numerous, almost colourless, spheres of matter appeared, which changed their forms and slowly coalesced; the appearance of the cells being thus totally changed at successive intervals of time. The glands on a young flower-stem, after having been left for 2 hrs. 45 m. in a strong solution of one part of the carbonate to 109 of water, contained an abundance of aggregated masses, but whether generated by the action of the salt, I do not know. This piece was again placed in the solution, so that it was immersed altogether for 6 hrs. 15m., and now there was a great change ; for almost all the spherical masses within the gland-cells had disappeared, being replaced by granular matter of a darker brown. The experiment was thrice repeated with nearly the sltme result. On one occasion the piece was left immersed for 8 hrs. 30 m., and though almost all the spherical masses were changed into the brown granular matter, a few still remained. If the spherical masses of aggregated matter had been originally produced merely by some chemical or physical action, it seems strange that a somewhat longer immersion in the same solution should so completely alter their character. But as the masses which slowly and spontaneously changed their forms · must have consisted of living protoplasm, there is nothing surprising. in its being injured or killed, and its appearance wholly changed by long immersion in so strong a solution of the carbonate as that |
