Chap. I. ACTION OF THE PAETS. 15 



tentacles remain closely inflected, the glands continue 

 to secrete, and the secretion is acid ; so that, if neu- 

 tralised by carbonate of soda, it again becomes acid 

 after a few hours. I have observed the same leaf with 

 the tentacles closely inflected over rather indigestible 

 substances, such as chemically prepared casein, pour- 

 ing forth acid secretion for eight successive days, and 

 over bits of bone for ten successive days. 



The secretion seems to possess, like the gastric juice 

 of the higher animals, some antiseptic power. During 

 very warm weather I placed close together two equal- 

 sized bits of raw meat, one on a leaf of the Drosera, 

 and the other surrounded by wet moss. They were 

 thus left for 48 hrs., and then examined. The bit on 

 the moss swarmed with infusoria, and was so much 

 decayed that the transverse striae on the muscular 

 fibres could no longer be clearly distinguished; 

 whilst the bit on the leaf, which was bathed by the 

 secretion, was free from infusoria, and its stri« were 

 perfectly distinct in the central and undissolved por- 

 tion. 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; whilst 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 secretion. The 

 drying of the glands during the act of re-expan- 

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

 often observed that objects adhering to the leaves 

 2 



