Chap. VI.] DIGESTION. 109 



given bits of meat, are inflected much more energetically and 

 quickly than they were before, notwithstanding that some 

 rest is generally requisite between two acts of inflection. We 

 probably see the influence of texture in gelatine and globulin 

 when softened by having been soaked in water acting more 

 quickly than when merely wetted. It may be partly due 

 to changed texture, and partly to changed chemical nature, 

 that albumen, which has been kept for some time, and gluten 

 which has been subjected to weak hydrochloric acid, act 

 more quickly than these substances in their fresh state. 



The length of time during which the tentacles remain 

 inflected largely depends on the quantity of the substance 

 given, partly on the facility with which it is penetrated or 

 acted on by the secretion, and partly on its essential nature. 

 The tentacles always remain inflected much longer over 

 large bits or lai^e drops than over small bits or drops. Tex- 

 ture probably plays a part in determining the extraordinary 

 length of time during which the tentacles remain inflected 

 over the hard grains of chemically prepared casein. But the 

 tentacles remain inflected for an equally long time over 

 finely powdered, precipitated phosphate of lime ; phosphorus 

 in this latter case evidently being the attraction, and animal 

 matter in the case of casein. The leaves remain long in- 

 flected over insects, but it is doubtful how far this is due 

 to the protection afforded by their chitinous integuments; 

 for animal matter is soon extracted from insects (probably 

 by exosmose from their bodies into the dense surrounding 

 secretion), as shown by the prompt inflection of the leaves. 

 We see the influence of the nature of different substances in 

 bits of meat, albumen, and fresh gluten acting very different- 

 ly from equal-sized bits of gelatine, areolar tissue, and the 

 fibrous basis of bone. The former cause not only far more 

 prompt and energetic, but more prolonged, inflection than 

 do the latter. Hence we are, I think, justified in believing 

 that gelatine, areolar tissue, and the fibrous basis of bone, 

 would be far less nutritious to Drosera than such substances 

 as insects, meat, albumen, <fec. This is an interesting con- 

 clusion, as it is known that gelatine affords but little nutri- 

 ment to animals; and so, probably would areolar tissue and 

 the fibrous basis of bone. The chondrin which I used acted 

 more powerfully than gelatine, but then I do not know that 



