242 DION^A MUSCIPULA. [Chap. XIII. 



end of the leaf ^vhere nothing had been placed began to 

 open, and on the third day was much more open than the 

 opposite end where the albumen had lain. 



Lastly, large drops of a solution of one part of carbonate 

 of ammonia to 146 of water were placed on some leaves, but 

 no immediate movement ensued. I did not then know of 

 the slow movement caused by animal matter, otherwise I 

 should have observed the leaves for a longer time, and they 

 would probably have been found closed, though the solution 

 (judging from Drosera) was, perhaps, too strong. 



From the foregoing cases it is certain that bits of meat 

 and albumen, if at all damp, excite not only the glands to 

 secrete, but the lobes to close. This movement is widely 

 different from the rapid closure caused by one of the fila- 

 ments being touched. We shall see its importance when 

 we treat of the manner in which insects are captured. There 

 is a great contrast between Drosera and Diontea in the eflfects 

 produced by mechanical irritation on the one hand, and the 

 absorption of animal matter on the other. Particles of 

 glass placed on the glands of the exterior tentacles of Dro- 

 sera excite movement within nearly the same time, as do 

 particles of meat, the latter being rather the most eflScient; 

 but when the glands of the disc have bits of meat given them, 

 they transmit a motor impulse to the exterior tentacles much 

 more quickly than do these glands when bearing inorganic 

 particles, or when irritated by repeated touches. On the 

 other hand, with Diontea, touching the filaments excites in- 

 comparably quicker movement than the absorption of animal 

 matter by the glands. Nevertheless, in certain cases, this 

 latter stimulus is the more powerful of the two. On three 

 occasions leaves were found which from some cause were 

 torpid, so that their lobes closed only slightly, however much 

 their filaments were irritated; but on inserting crushed in- 

 sects between the lobes, they became in a day closely shut. 



The facts just given plainly show that the glands have 

 the power of absorption, for otherwise it is impossible that 

 the leaves should be so differently affected by non-nitroge- 

 nous bodies, and between these latter in a dry and damp con- 

 dition. It is surprising how slightly damp a bit of meat or 

 albumen need be in order to excite secretion and afterwards 

 slow movement, and equally surprising how minute a quan- 



