2t)4 DROSERA ROTUNDIFOLIA. CHAP XI. 



though with considerable force and with a hard object, 

 the tentacle does not bend. The plant is thus saved 

 from much useless movement, as during a high wind 

 the glands can hardly escape being occasionally 

 brushed by the leaves of surrounding plants. Though 

 insensible to a single touch, they are exquisitely sensi- 

 tive, as just stated, to the slightest pressure if pro- 

 longed for a few seconds ; and this capacity is mani- 

 festly of service to the plant in capturing small 

 insects. Even gnats, if they rest on the glands with 

 their delicate feet, are quickly and securely embraced. 

 The glands are insensible to the weight and repeated 

 blows of drops of heavy rain, and the plants are thus 

 likewise saved from much useless movement. 



The description of the movements of the tentacles 

 was interrupted in the third chapter for the sake oi 

 describing the process of aggregation. This process 

 always commences in the cells of the glands, the con- 

 tents of which first become cloudy ; and this has 

 been observed within 10 s. after a gland has been 

 excited. Granules just resolvable under a very high 

 power soon appear, sometimes within a minute, in the 

 cells beneath the glands ; and these then aggregate 

 into minute spheres. The process afterwards travels 

 down the tentacles, being arrested for a short time at 

 each transverse partition. The small spheres coalesce 

 into larger spheres, or into oval, club-headed, thread- 

 or necklace-like, or otherwise shaped masses of proto- 

 plasm, which, suspended in almost colourless fluid, 

 exhibit incessant spontaneous changes of form. These 

 frequently coalesce and again separate. If a gland 

 has been powerfully excited, all the cells down to the 

 base of the tentacle are affected. In cells, especially 

 if filled with dark red fluid, the first step in the 



