THE ANIMAL A MACHINE H)'.) 



choice. The whole proceeding may seem at first thought very absurd, but 

 the results are striking. 



We may first offer the drop of chloroform a fragment of glass; this is held 

 with the tweezers against the surface of the drop. It is not accepted. We 

 push the glass against the drop, but the latter withdraws its surface from 

 it as far as possible. We force the bit of glass into the drop of chloroform 

 and let go of it. It is at once thrown out with energy. We try a small 

 piece of wood in the same way; it is rejected as decidedly as was the glass. 

 We may now try a hard piece of gum shellac. This is accepted eagerly, one 

 had almost said. Hardly has an angle of the piece of shellac touched the 

 surface of the drop, when the latter literally reaches out, envelops the 

 shellac and draws it into itself. If we take hold of the piece of shellac 

 again with the forceps and draw it away, the chloroform drop stretches out 

 after it, and lets go of it only with the greatest apparent reluctance. If 

 allowed to retain the bit of shellac, it proceeds slowly to dissolve it, — just 

 as the Amoeba proceeds to digest the substance which it has taken within 

 itself. A second and a third piece of shellac will be accepted with the same 

 avidity as the first. 



Other substances may be offered to the chloroform drop. Glass, sand, 

 dirt, wood, grass, gum arabic, and chlorate of potash, for example, are 

 rejected; shellac, paraffin, styrax, hard Canada balsam, and various other 

 substances are accepted. 



It thus appears that a drop of chloroform exercises choice in determining 

 what substances will be taken into itself, fully as decidedly as Amoeba does. 

 The same is true of other fluids, of whatever sort. We must then throw out 

 completely the power of choice of food as any test of mental power or even 

 of life. Amoeba merely shares this power with all other masses of fluid. 

 It is a suggestive fact, and one which has possibly a deep significance, that 

 the chloroform drop (or other fluids) tends to take into itself especially 

 such substances as will dissolve within it, or have a chemical affinity for it, 

 just as Amoeba tends to take within itself substances which it can digest. 



E. The Intake of Long Pieces of Food 



The intake of long pieces of food larger than itself is 

 another striking feature of Amoeba. Can the oil-drop 

 perform such a seemingly difficult task? Professor Jen- 

 nings' colorful description answers this question: 



The method by which Amoeba takes a small particle of food is very 

 similar to that by which the chloroform drop takes within itself a bit of 

 gum shellac. The protoplasm simply flows over and envelops the food 

 particle. But at times the problem presented to the Amoeba, if food is to 

 be obtained, is much more difficult. Sometimes the food available is in the 

 form of a long thread of alga, many times the length of the Amoeba. How 



