Chap. XL] GENERAL SUMMARY. 213 



CHAPTER XI. 



RECAPITULATION OF THE CHIEF OBSERVATIONS ON 

 DROSERA ROTUNDIFOLIA.' 



As summaries have been given to most of the chapters, it 

 will be sufficient here to recapitulate, as briefly as I can, the 

 chief points. In the first chapter a preliminary sketch was 

 given of the structure of the leaves, and of the manner in 

 which they capture insects. This is effected by drops of 

 extremely viscid fluid surrounding the glands and by the 

 inward movement of the tentacles. As the plants gain most 

 of their nutriment by this means, their roots are very poorly 

 developed; and they often grow in places where hardly any 

 other plant except mosses can exist. The glands have the 

 power of absorption, besides that of secretion. They are ex- 

 tremely sensitive to various stimulants, namely repeated 

 touches, the pressure of minute particles, the absorption of 

 animal matter and of various fluids, heat, and galvanic ac- 

 tion. A tentacle with a bit of raw meat on the gland has 

 been seen to begin bending in 10 s., to be strongly incurved 

 in 5 m., and to reach the centre of the leaf in half an hour. 

 The blade of the leaf often becomes so much inflected that it 

 forms a cup, enclosing any object placed on it. 



A gland, when excited, not only sends some influence 

 down its own tentacle, causing it to bend, but likewise to 

 the surrounding tentacles, which become incurved; so that 

 the bending place can be acted on by an impulse received 

 from opposite directions, namely from the gland on the sum- 

 mit of the same tentacle, and from one or more glands of the 

 neighbouring tentacles. Tentacles, when inflected, re-ex- 

 pand after a time, and during this process the glands secrete 

 less copiously or become dry. As soon as they begin to se- 

 crete again, the tentacles are ready to re-act; and this may 

 be repeated at least three, probably many more times. 



> [The reader consulting this the list of additions In the pres- 

 chapter. without hnvlns road the ent e<)ltion given at the beginning 

 foregoing pages should look at of the book. B\ D.] 



