THE SUNDEWS. 39 



the leaf; in the other case by the glands of the 

 mucous membrane. In both the act of secretion is 

 excited by the presence of the substance to be 

 digested. In the leaf, just as in the stomach, the 

 secretion is not poured out unless there is something 

 nutritious in it for it to act upon ; and, finally, in 

 both cases the secretion is acid. As regards the 

 stomach we know what the acid is, — it is hydrochloric 

 acid. As regards the leaf we do not know precisely 

 as yet, but Mr. Darwin has been able to arrive at very 

 probable conclusions." 



It has been demonstrated, by experiment, that the 

 secretion of the glands of the sundew completely 

 dissolves albumen, muscle, fibrin, cartilage, the fibrous 

 portion of bone, gelatin, and the casein of milk. That 

 is to say, little cubes of hard-boiled egg, fragments of 

 roast meat, tough cartilage from a leg-bone of mutton, 

 small pieces of the bone of a fowl, and of a mutton- 

 chop bone, the latter being so softened that it might 

 be penetrated by a blunt needle, or compressed, and 

 these became dissolved as they would have been 

 in the stomach of some of the higher animals. 



It is only necessary to cite one experiment which 

 was performed on a most unpromising substance 

 under somewhat unfavourable conditions. "Three 

 cubes of white translucent, extremely tough cartilage 

 were cut from the end of a slightly-roasted leg-bone 

 of a sheep. These were placed on three leaves, borne 



