CHAPTER X 



THEIR PLACE IN NATURE 



IN the endless chain of Evolution of life on the 

 earth it is easy to place microbes. They are them- 

 selves a part of that evolution the first part. 

 They are the connecting link between all other life 

 above them and the mineral below them. Imagine 

 the tiniest possible speck of protoplasm. It is the 

 first speck of life on earth above the mineral. The 

 word protoplasm means "first life." From this 

 speck may be traced three distinct lines of evolu- 

 tion, severally ending in the complete development 

 of the three general types or sub-kingdoms. Fig. 

 43 shows different stages in the evolution of the 

 first type. The first stage is the tiny speck of pro- 

 toplasm. It is microscopic millions of times 

 smaller than the tiniest drop of water. The sub- 

 stance is jelly-like, and has no envelope or covering. 



In the second stage the tiny speck has multiplied, 

 and its offspring are larger. In the third stage the 

 individuals are fully developed and have an en- 

 velope. In the fourth stage they have acquired the 

 power of extemporizing legs for locomotion. 



Fig. 44 shows four similar stages in the evolution 

 of the Rod Shaped type and Fig. 45 shows the four 

 stages in the evolution of the Spiral Shaped type. 



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