OF LIVING MATTER 37 



passing by dialysis into the surrounding protoplasm, by which 

 they are assimilated. All the steps of this process, including an 

 account of the movements of Amceb^e, the mode in which they 

 take foreign bodies into their interior, the origin of the vacuoles, 

 and what goes on therein, are well told by le Dantec {loc. cit. 

 pp. 65-104), but need not detain us here. 



So far as the process of ' digestion ' is concerned it is admitted 

 by all that the phenomena are essentially chemical in all cases, and 

 that with the aid of enzymes the process can be carried on outside 

 the body, under suitable artificial conditions, with perfect ease. 

 There is no mystery here — the mystery, in the sense of our 

 ignorance of the exact steps of the process, rests rather with the 

 subsequent assimilative processes which, as we have indicated, 

 are similar in kind whether we have to do with independent living 

 units or with the constituent elements of higher organisms. 



In certain cases, however, both Amoebae, Ciliated Infusoria, and 

 Sun Animalcules take into their bodies comparatively large masses 

 of food, which may not be contained in vacuoles, but may be in 

 immediate contact with their own protoplasm, where it becomes 

 rapidly transformed and assimilated. Nothing is more astonishing 

 than the capacity of this kind displayed by many Amoebae or 

 Ciliated Infusoria. The writer has several times seen a large 

 Amoeba containing in its interior a Rotifer of half its own bulk 

 undergoing digestion ; while it is the commonest thing possible 

 to see in decaying cells of Nitella certain Amcebas growing rapidly 

 as they gorge themselves with Chlorophyll corpuscles, till at last 

 they form motionless spheres so densely packed with chlorophyll 

 that nothing else can be seen except a limiting membrane, as 

 shown in the writer's " Studies in Heterogenesis " PI. XVI., fig. 164 ; 

 and yet, as a reference to p. 251 of that work will show, in the 

 space of no more than ten hours the whole of that chlorophyll, 

 with progressive changes in colour, becomes rapidly digested and 

 assimilated — converted, in fact, into colourless protoplasm, which 

 within the same space of time has, moreover, often more or less 

 completely segmented into Monads. 



The rapidity of this process is so surprising as to be almost 

 incredible to one who has not himself seen it occurring. Yet 

 almost exactly the same kind of thing occurs with specimens of 

 a Ciliate belonging to the genus Otostoma, found at times in 

 decaying Nitella. These creatures also gorge themselves with 

 chlorophyll till they appear only like great, green ciliated balls ; 



