Chap. I.] ACTION OP THE PARTS. 13 



in the central and undissolved portion. In like manner small 

 cubes of albumen and cheese placed on wet moss became 

 threaded with filaments of mould, and had their surfaces 

 slightly discoloured and disintegrated; Avhilst those on the 

 leaves of Drosera remained clean, the albumen being changed 

 into transparent fluid. 



As soon as tentacles, which have remained closely inflected 

 during several days over an object, begin to re-expand, their 

 glands secrete less freely, or cease to secrete, and are left 

 dry. In this state they are covered with a film of whitish, 

 semi-fibrous matter, which was held in solution by the se- 

 cretion. The drying of the glands during the act of re- 

 expansion is of some little service to the plant; for I have 

 often observed that objects adhering to the leaves could then 

 be blown away by a breath of air; the leaves being thus left 

 unencumbered and free for future action. Nevertheless, it 

 often happens that all the glands do not become completely 

 dry; and in this case delicate objects, such as fragile insects, 

 are sometimes torn by the re-expansion of the tentacles into 

 fragments, which remain scattered all over the leaf. After 

 the re-expansion is complete, the glands quickly begin to re- 

 secrete, and, as soon as full-sized drops are formed, the tenta- 

 cles are ready to clasp a new object. 



When an insect alights on the central disc, it is instantly 

 entangled by the viscid secretion, and the surrounding tenta- 

 cles after a time begin to bend, and ultimately clasp it on all 

 sides. In^pcts are generally killed, according to Dr. Nitschke, 

 in about a quarter of an hour, owing to their tracheae being 

 closed by the secretion. If an insect adheres to only a 

 few of the glands of the exterior tentacles, these soon become 

 inflected and carry their prey to the tentacles next succeeding 

 them inwards; these then bend inwards, and so onwards, 

 until the insect is .ultimately carried by a curious sort of roll- 

 ing movement to the centre of the leaf. Then, after an inter- 

 val, the tentacles on all sides become inflected and bathe their 

 prey with their secretion, in the same manner as if the insect 

 had first alighted on the central disc. It is surprising how 

 minute an insect sufiices to cause this action : for instance, I 

 have seen one of the smallest species of gnats (Culex), which 

 had just settled with its excessively delicate feet on the glands 

 of the outermost tentacles, and these were already beginning 



