THE PLANT AND THE ANIMAL 



255 



u -M-H 





we mark in one way or another the position of these 

 semi-liquid masses (called plasmodia) and remember 

 their outlines, we shall be greatly surprised in a short 

 time to notice that they have moved considerably from 

 the place they occupied and have also changed their 

 shape. By observing one of the fine branches of a 

 Plasmodium, or better still by examining it under a 

 microscope, we come to 

 the conclusion that it 

 actually does move. 

 These branches form 

 protuberances, pseudo- 

 podia, into which the 

 protoplasm of the neigh- 

 bouring parts flow. The 

 protuberance so formed 

 is soon drawn back again 

 and becomes absorbed 

 into the general mass ; 

 another one appears 

 drawing the protoplasm 

 in its turn. Thus 

 stretching and contracting again the plasmodium creeps 

 about (figs. 72 and 73) , tending for the most part in some 

 definite direction ; it changes its position, creeps towards 

 the light at the top of the pile, out from the inside of it, 

 where it was concealed, crawls over every object in its 

 path, e.g. a sheet of paper or glass — in a word it wanders, 

 until it is arrested by the approach of the period of re- 

 production. Then it transforms itself into an indefinite 

 scone-like shape, the size of the palm of the hand, with a 

 very brittle wail, and inside a very fine dust is formed, 

 reminding us of the dust we raise when we tread on a 

 ripe puff-ball. This dust consists mainly of minute 

 cells, spores, serving to reproduce the organism. In 

 germinating, the spores of our slime fungus shed their 

 cell-wall and soon transform themselves into micro- 



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Fig. 72. 



