[122]

(47

Ch XI

the viscid secretion, & touches with one of its points the surface of the gland does not act produce any effect. A little bit of a thin human hair 8/1000th of an inch in length, & weighing only 1/78.700th of a grain, though largely supported by the dense secretion sufficed to induce movement. Even smaller atoms particles cause a slight movement, as could be plainly seen through a lens. The excite sensitiveness of the glands to so slight a pressure is truly wonderful. Particles of this size cause no sensation when placed on the most delicate part of the human finger of a man or in the his tongue.

movement ensues if a gland may be if be is momentarily touched, once or twice three or four times; by a hard object & with considerable force & no movement ensued; but if touched three or four or more times, or repeatedly as by a strong [illeg] subject but if touched only once or twice, though with considerable will force & with a hard object the tentacle does not bend. bends become inflected. The plant is thus saved from much useless movement, as during a high wind the glands could hardly escape being occasionally touched brushed by the leaves of the surrounding plants. Though insensible to a single touch, they are exquisitely sensitive, as just stated, to the slightest pressure

[122v]

Flower crossed by pollen of other plants

Eschotzia

[calculations not transcribed]