SPECIAL ADAPTATIONS 377 



pepsin, and a rennet ferment 1 . *No inverting ferment has been detected in 

 Mucor alternans and M. circinelloides nor in certain yeasts' 2 . 



Myxomycetes exhibit all stages of transition between active and imperceptible 

 extracellular and intracellular fermentative activities. Thus Chondrioderma and 

 Aethalium septicum 3 corrode ingested starch grains and proteids but feebly and 

 are not always able to digest them. On the other hand Plasmodiophora Brassicae 

 penetrates living plants, Vampyrella vorax and Leptophrys Kutzingii kill and digest 

 algae, while Monas amyli rapidly dissolves starch grains 4 . Vampyrella and Lepto- 

 phrys kill their prey, whereas organisms ingested by Aethelium and Chondrioderma 

 remain living, and bacteria may even increase in numbers within their vacuoles 5 . 

 The latter Myxomycetes may be cultivated in sterile fluid media in which no solid 

 food particles are present, whereas it is not known whether the same is the case 

 with Vampyrella and Leptophrys. In these plants, and in the Flagellata and Ciliata 

 as well, all grades of transition probably exist from organisms which absorb their 

 food in fluid form only, to those which can digest solid food 6 . 



Carnivora. Many plants live upon animal or vegetable food, or upon 

 a mixture of both. Various bacteria and the fungi parastic upon insects 

 are purely carnivorous, whereas no phanerogam can be cultivated upon an 

 exclusively proteid diet, although the so-called ' carnivorous plants' obtain 

 a small amount of organic food by the capture and digestion of insects. 



With regard to the special peculiarities of carnivorous plants a few 

 points only can be mentioned, and for further details reference must be 

 made to the literature quoted beneath 7 . Thus in Nepenthes (Fig. 56) 

 insects are drowned in pitchers partially filled with water, in Dionaea 

 (Fig. 57, A and B] and Aldrovanda they are captured by the sudden 

 closure of the -hinged leaf when it is mechanically irritated, while in Drosera 

 (Fig. 58), Drosophyllum, and Pinguicula an insect may be retained by means 

 of a sticky secretion. The contrivances used in the capture of insects are 

 therefore such as are employed by other plants for different purposes, and 

 so are the means of attraction by scent, colour, nectar, &c., for these play 



1 Bruhne, in Zopfs Beitrage z. Phys. u. Morph. nied. Org., 1894, I, p. 26. 



2 Mucor: Gayon, Ann. d, sci. nat,, 1882, vi. se"r., T. xiv, p. 46. Yeast : Beyerinck, Centralbl. 

 f. Bact., 1893, Bd. XI, p. 70. 



3 Celakovsky, Flora, Erg.-bd., 1892, p. 227, where the fact is mentioned that Krukenberg suc- 

 ceeded in obtaining a proteolytic enzyme from Aethalium. 



* Cf. de Bary, Pilze, 1884, p. 481 ; Zopf, Unters. iiber Monadineen, 1887, p. 24. 



5 Celakovsky, I.e., p. 224; Pfeffer, Aufnahme ungelbster Korper, 1890, p. 153. 



6 Sect. 19. Cf. Biitschli, Protozoen, 1883-9, Bd - n P- 6 94! Bd ' nr P' x ?97 5 Greenwood, 

 Biol. Centralbl., 1894, Bd. xiv, p. 777. 



7 Darwin, Carnivorous Plants, 1875 ; Geddes, Article in Encyc. Brit. ; Goebel, Pflanzenbiol. 

 Schilderungen, 1891-3, II, p. 53; Kerner, Natural History of Plants, 1896, Vol. I, p. 118. Several 

 doubtful examples are given here. On Lathraea, see Scherffel, Bot. Zeitung, 1890, p. 416; Hein- 

 richer, Ber. d. Bot. Ges., 1893, p. 7; Haberlandt, Jahrb. f. wiss. Bot., 1897, Bd. xxx, p. 511 ; 

 Goebel, Flora, 1897, p. 444. On Polyporus apflfinatus, MacMillan, Bot. Centralbl., 1893, Bd. LIII, 

 p. 3 22 - 



