172 life's beginning on the earth 



of chloroform floating on the surface of the water is used, though the 

 experiment is otherwise much more difficult to perform under these circum- 

 stances. Thereupon the thread bends, exactly as with Amoeba. The 

 process now continues, precisely parallel with what occurs in the case of 

 Amoeba and the alga thread, until the shellac thread is coiled up within the 

 chloroform drop, like a filament of an alga within an Amoeba. . . . 



(Chloroform is a liquid which is heavier than water and 

 does not mix with it. Hence it usually sinks to the bottom 

 of water. Small droplets of chloroform, however, may float 

 on top, being held there by surface tension.) 



F. Defecation 



It seems almost ridiculous to speak of defecation in the 

 Amoeba, which is not much more than a drop without any 

 body openings. What is meant here is the expelling from 

 the body of the Amoeba of certain indigestible particles, 

 for instance of sand, which were embedded in soft plant food 

 which the animal had taken. The Amoeba first takes up 

 all it can and expels the sand later. 



It would seem that an oil-drop is incapable of imitating 

 this procedure, for one could hardly expect the oil-drop to 

 defecate. And yet it is done. To demonstrate this point 

 we proceed as follows: A tiny thread of glass is coated with 

 shellac. Upon touching it with the chloroform drop, the 

 drop will "devour" it. The coated glass thread is kept 

 inside the drop until the shellac coat is dissolved. As soon 

 as this is done, the drop ''defecates" or expels this naked 

 bit of glass, but retains the shellac. (According to an ex- 

 periment described by a German Scientist, L. Rhumbler.) 



G. Shells of Sand or Glass Fragments 



Another striking feature capable of imitation is the forma- 

 tion of shells of sand around certain other primitive animals, 

 which Professor Jennings describes (Cp. Figs. 09 and 70): 



As is well known, DifUugia, one of the close relatives of Amoeba, lives 

 in a shell formed of sand grains, diatom shells, and other small particles 



