308 PINGUICULA VULGARIS. [Chap. XVI. 



vent insects from being washed away by the rain; but it 

 likewise serves for another end. When a number of glands 

 have been powerfully excited by bits of meat, insects, or any 

 other stimulus, the secretion often trickles down the leaf, 

 and is caught by the incurved edges, instead of rolling off 

 and being lost. As it runs down the channel, fresh glands 

 are able to absorb the animal matter held in solution. More- 

 over, the secretion often collects in little pools within the 

 channel, or in the spoon-like tips of the leaves; and I ascer- 

 tained that bits of albumen, fibrin, and gluten are here dis- 

 solved more quickly and completely than on the surface of 

 the leaf, where the secretion cannot accumulate; and so it 

 would be with naturally caught insects. The secretion was 

 repeatedly seen thus to collect on the leaves of plants protect- 

 ed from the rain; and with exposed plants there would be 

 still greater need of some provision to prevent, as far as pos- 

 sible, the secretion, with its dissolved animal matter, being 

 wholly lost. 



It has already been remarked that plants growing in a 

 state of nature have the margins of their leaves much more 

 strongly incurved than those grown in pots and prevented 

 from catching many insects. We have seen that insects 

 washed down by the rain from all parts of the leaf often 

 lodge within the margins; which are thus accited to curl 

 farther inwards; and we may suspect that this action, many 

 times repeated during the life of the plant, leads to their 

 permanent and well-marked incurvation. I r^ret that this 

 view did not occur to me in time to test its truth. 



It may here be added, though not immediately bearing on 

 our subject, that when a plant is pulled up, the leaves im- 

 mediately curl downwards so as to almost conceal the roots, 

 a fact which has been noticed by many persons. I sup- 

 pose that this is due to the same tendency which causes the 

 outer and older leaves to lie flat on the ground. It further 

 appears that the flower-stalks are to a certain extent irrita- 

 ble, for Dr. Johnson states that they " bend backwards if 

 rudely handled."* 



* ' Kntrllth notnnv,' by Sir J. turgeBCPnt Btom. This wonld be 



E. Smith; with coloured flRnros likely to occur In the course of 



by J. Sowerhy; edit, of IKtt. tub. the " roujfh handling." and we 



24. 2r. 'M. (It Ir well known that may porhnps thus account for Dr. 



permanent curvatures may be Johnson's curvatures. P. D.] 

 produced by bending or shaking a 



