852 GLANDULAK HAIRS,' Chap. XV. 



in amount ; but one such mass retained exactly the same form as 

 before after an interval of 5 hrs., so that it could hardly have 

 consisted of living protoplasm. These glands seem to have very 

 little or no power of absorption, certainly much less than those 

 of the foregoing plants. 



Mirahilis longiflora. — The stems and both surfaces of the 

 leaves bear viscid hairs. Young plants, from 12 to 18 inches 

 in height in my greenhouse, caught so many minute Diptera, 

 Coleoptera, and larvae, that they were quite dusted with them. 

 The hairs are short, of unequal lengths, formed of a single row 

 of cells, surmounted by an enlarged cell which secretes viscid 

 matter. These terminal cells or glands contain granules and 

 often globules of granular matter. Within a gland which had 

 caught a small insect, one such mass was observed to undergo 

 incessant changes of form, with the occasional appearance of 

 vacuoles. But I do not believe that this protoplasm had been 

 generated by matter absorbed from the dead insect; for, 

 on comparing several glands which had and had not caught 

 insects, not a shade of difference could be perceived between 

 them, and they all contained fine granular matter. A piece of 

 leaf was immersed for 24 hrs. in a solution of one part of car- 

 bonate of ammonia to 218 of water, but the hairs seemed very 

 little affected by it, excepting that perhaps the glands were 

 rendered rather more opaque. In the leaf itself, however, the 

 grains of chlorophyll near the cut surfaces had run together, 

 or become aggregated. Nor were the glands on another leaf, 

 after an immersion for 24 hrs. in an infusion of raw meat, in 

 the least affected; but the protoplasm lining the cells of the 

 pedicels had shrunk greatly from the walls. This latter effect 

 may have been due to exosmose, as the infusion was strong. 

 We may, therefore, conclude that the glands of this plant either 

 have no power of absorption or that the protoplasm which they 

 contain is not acted on by a solution of carbonate of ammonia 

 (and this seems scarcely credible) or by an infusion of meat. 



Nicotiana tabacum. — This plant is covered with innumerable 

 hairs of unequal lengths, which catch many minute insects. 

 The pedicels of the hairs are divided by transverse partitions, 

 and the secreting 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 for 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 



