Chap. XV.] SECRETION. 278 



acquired the habit of secreting copiously when stimulated; 

 whereas with Drosera this is of use, and the habit has been 

 acquired. Nevertheless, the glands of Drosophyllum, with- 

 out being stimulated, continually secrete, so as to replace 

 the loss by evaporation. Thus when a plant was placed 

 under a small bell-glass with its inner surface and support 

 thoroughly wetted, there was no loss by evaporation, and so 

 much secretion was accumulated in the course of a day that 

 it ran down the tentacles and covered large spaces of the 

 leaves. 



The glands to which the above named nitrogenous sub- 

 stances and liquids were given did not, as just stated, se- 

 crete more copiously; on the contrary, they absorbed their 

 own drops of secretion with surprising quickness. Bits of 

 damp fibrin were placed on five glands, and when they were 

 looked at after an interval of 1 hr. 12 m., the fibrin was 

 almost dry, the secretion having been all absorbed. So it 

 was with three cubes of albumen after 1 hr. 19 m., and with 

 four other cubes, though these latter were not looked at 

 until 2 hrs. 15 m. had elapsed. The same result followed 

 in between 1 hr. 15 m. and 1 hr. 30 m. when particles both of 

 cartilage and meat were placed on several glands. Lastly, a 

 minute drop (about ^ of a minim) of a solution of one part 

 of nitrate of ammonia to 146 of water was distributed be- 

 tween the secretion surrounding three glands, so that the 

 amount of fluid surrounding each was slightly increased; 

 yet when looked at after 2 hrs., all three were dry. On the 

 other hand, seven particles of glass and three of coal-cinders, 

 of nearly the same size as those of the above-named organic 

 substances, were placed on ten glands; some of them being 

 observed for 18 hrs., and others for two or three days; but 

 there was not the least sign of the secretion being absorbed. 

 Hence, in the former cases, the absorption of the secretion 

 must have been due to the presence of some nitrogenous 

 matter, which was either already soluble or was rendered so 

 by the secretion. As the fibrin was pure, and had been well 

 washed in distilled water after being kept in glycerine, and 

 as the cartilage had been soaked in water, I suspect that 

 these substances must have been slightly acted on and ren- 

 dered soluble within the above stated short periods. 



The glands have not only the power of rapid absorption. 



