Chap. XV.] THEIR POWER OP ABSORPTION. 287 



of Saxifraga, as this genus is distantly allied to Drosera. 

 Their glands absorb matter from an infusion of raw meat, 

 from solutions of the nitrate and carbonate of ammonia, and 

 apparently from decayed insects. This was shown by the 

 changed dull purple colour of the protoplasm within the cells 

 of the glands, by its state of aggregation, and apparently by 

 its more rapid spontaneous movements. The aggregating 

 process spreads from the glands down the pedicels of the 

 hairs; and we may assume that any matter which is ab- 

 sorbed ultimately reaches the tissues of the plant. On the 

 other hand, the process travels up the hairs whenever a sur- 

 face is cut and exposed to a solution of the carbonate of am- 

 monia. 



The glands on the flower-stalks and leaves of Primula 

 sinensis quickly absorb a solution of the carbonate of am- 

 monia, and the protoplasm which they contain becomes ag- 

 gregated. The process was seen in some cases to travel from 

 the glands into the upper cells of the pedicels. Exposure for 

 10 m. to the vapour of this salt likewise induced aggregation. 

 When leaves were left from 6 hrs. to 7 hrs. in a strong solu- 

 tion, or were long exposed to the vapour, the little masses of 

 protoplasm became disintegrated, brown, and granular, and 

 were apparently killed. An infusion of raw meat produced 

 no effect on tlie glands. 



The limpid contents of the glands of Pelargonium zonale 

 became cloudy and granular in from 3 m. to 5 m. when they 

 were immersed in a weak solution of the carbonate of am- 

 monia; and in the course of 1 hr. granules appeared in the 

 upper cells of the pedicels. As the aggregated masses slowly 

 changed their forms, and as they suffered disintegration 

 when left for a considerable time in a strong solution, there 

 can be little doubt that they consisted of protoplasm. It is 

 doubtful whether an infusion of raw meat produced any 

 effect. 



The glandular hairs of ordinary plants have generally 

 been considered by physiologists to serve only as secreting 

 or excreting organs, but we now know that they have the 

 power, at least in some cases, of absorbing both a solution 

 and the vapour of ammonia. As rain-water contains a small 

 percent^e of ammonia, and the atmosphere a minute quan- 

 tity of the carbonate, this power can hardly fail to be 



