8 PROBLEMS OF EVOLUTION 



organism in question is found on dead leaves or other things 

 in stagnant water, and is called the amoeba, i.e. the changeable, 

 the Protean. 1 It can hardly be seen without the aid of a 

 microscope since its diameter is not more than TOO of an inch. 

 To search for it, a low power is best : when it has been 

 found, a higher power (a J or J inch glass) should be used. 



The amoeba is excellently described in Parker's Lessons in 

 Elementary Biology where justice is done to every trait in its char- 

 acter. It is a little blob of jelly, or, to use the scientific term, 

 protoplasm. The greater part of its extent is greyish and 

 granulated, but surrounding this is a narrow margin of -trans- 

 parent material. If the amoeba is active, as according to its 

 name it should be, it will be seen soon to extend a tongue 

 of its transparent substance in one direction or another, and 

 then the granulated grey will begin to stream into the pro- 

 truded transparent tongue. As you watch its movements it 

 seems like an uncanny piece of inorganic matter moved by 

 some power not its own, rather than a living being. At times 

 in its life come periods of torpor. Possibly because the con- 

 ditions are adverse, or for other reasons unknown, it will form 

 round itself a chitinous case or cyst similar in composition 

 to the shell of the lobster. 



The constituents of the protoplasm of which the amoeba 

 is composed are mainly those that make up the substances 

 known as proteids viz., carbon, oxygen, nitrogen, hydrogen, 

 sulphur. The carbon forms more than 50 per cent, of the 

 whole, and I have arranged them all in order according to 

 the amount which they contribute. These with a good deal 

 of water and some mineral matter compose protoplasm, and 

 protoplasm is the essential constituent of all organisms whether 

 animal or vegetable. 



An amoeba has no strong cell-wall surrounding it ; and as it 

 flows about, if it comes in contact with anything edible (such as 

 a diatom, a minute vegetable with a flinty covering), its proto- 

 plasm closes round it, and the diatom is, to use the correct term, 



1 Should the reader search in vain for Amcebse, he may for one shilling obtain a 

 number in a tuiie from Mr Bolton, 25 Balsall Heath Road, Birmingham. 



