

The Completeness of Lowest Forms 83 



each cell is found some of the green substance (chlorophyl or 

 leaf -green) characteristic of our common green plants. This 

 is known to be an essential factor in the making of starch 

 from water and carbon dioxid. The process of starch- 

 making goes on only in the presence of light. From the 

 starch, in the presence of other raw material absorbed with 

 water from the dust on its resting place, the greenslime makes 

 other food material. The 

 food material is con- 

 verted by the proto- 

 plasm into more pro- 

 toplasm, resulting in the 

 growth of the cell. 



After reaching a cer- 

 tain size the single green- 

 slime cell, or the single 

 bacterium, divides, like 

 an ameba, into two cells. 

 Each new cell is a com- 

 plete individual, differ- 

 ing from the mother-cell 

 only in size. In other 

 one-celled plants, like 

 the common baker's or 

 brewer's yeast (Fig. 19), 

 the growing cell puts 

 forth little extensions or 



" buds," which in turn continue to absorb nourishment from 

 the surrounding fluid, and to grow. This budding appears 

 to be a specialized mode of cell-division, for if a bud falls off 

 it may continue to grow like an independent cell. 



Fig. 19. Yeast Plant 



The cells of this plant multiply by pushing out 

 buds. Under certain conditions the protoplasm 

 of a cell divides into two and then four parts, 

 which then can remain inactive for an indefinite 

 time. These resting cells are called spores. From 

 Gruenberg, Elementary Biology, published by 

 Ginn & Company. 



The Completeness of Lowest Forms 



We call these very simple plants and animals " lower "; 

 and we think of birds and sunflowers as '' higher." Yet the 

 lowest living things appear to be as well adapted to living 



