PLANTS WHICH EXHIBIT MOVEMENTS IN THE CAPTCRE OF PREY. 143- 



is exceedingly like that of the animal stomach, and the process may, as in the case 

 of Nepenthes, be fairly regarded as digestion. Whether, in carrying out this 

 process, the different forms of glands have also different functions, whether those 

 of one kind serve principally to secrete and those of the other to absorb, or 

 whether, perhaps, the one variety only discharges viscid mucilage to capture the 

 prey, and the other only a liquid containing acid and pepsin, are questions not yet 

 determined with certainty, although such a division of labour is in itself highly 

 pi'obable. 



The similarity existing between the leaf of Pinguicida and the animal stomaoh 

 in respect of their action on albuminous substances was turned to a practical 

 application in dairy-farming long before the discovery of the relationship by men 

 of science. The very same changes as are brought about in milk bj' the addition 

 of the rennet from a calf's stomach can be induced by means of butterwort leaves. 

 If fi-esh milk, warm from the cow, is poured over these leaves, a peculiar tough 

 mass of close consistence is formed, the " Tätmiölk " or " Sätmiölk " of Laplanders, 

 mentioned by Linnjeus a hundred and fifty years ago as constituting a very 

 favourite dish in northern Scandinavia. In particulai', the fact that by means 

 of a trifling quantity of Tätmiölk, pi-oduced in the manner described, a large 

 amount of fresh sweet milk may be also converted into Tätmiölk is specially 

 worthy of emphasis, for we leai-n from it that the substance generated by 

 Pinguicida behaves in this respect too, like other ferments. The immemorial use 

 of Pinguicida leaves by shepherds in the Alps as a cure for sores on the udders 

 of milch cows is also interesting, inasmuch as the curative eflect on the sores is to 

 be explained by the antiseptic action of the secretion of the leaves in question, 

 and a method of healing, used empirically two ceutui-ies ago, thus finds confirmation 

 and a scientific explanation at the present day. 



Since the curling up and unrolling of the leaf-margin in butterwoi't is 

 accomplished but slowly, the process above described is not at all conspicuous. 

 Moreover, the margin of a young leaf is always incurved, and that of a mature 

 leaf is also somewhat turned up before stimulation has taken place; so that, strictly 

 speaking, we only have to do with a greater or smaller degree of involution, and its 

 nature can only be determined by careful observation. 



In the plants which form the second group in this section of carnivorous 

 plants, and of which the best known representatives are the various species of the 

 genus Sun-dew (Drosera), the movements, whi>reby the capture and digestion of 

 small animals is efiected, occur much more rapidly and obviously. These species 

 are usually rooted in the damp dark soil of moors. They have also the same 

 habitats as Pinguiculse, and often enough sun-dew and butterwort are to be seen 

 flourishing close together on a strip of boggy ground no larger than one's hand. 

 On Plate II. they are shown thus associated. Drosera rotiondifolia, together 

 with Pinguicida vulgaris, is there represented, life size, growing in a bed of 

 sphagnum amongst sedges on an upland moor. The thing that strikes one most at 

 sight of the round-leaved sun-dew depicted, and in general of all the forty known 



