What Bacteria Do 27 



a poisonous toadstool instead. We simply 

 trust to the gardener, or, if he be dishonest 

 or ignorant, see to it ourselves that the poison- 

 ous are not liable to get in with the other 

 plants, and then go on enjoying our delicacies 

 like sensible people. 



It will thus be seen that the r61e of the 

 bacteria in nature, though humble and silent, 

 is an exceedingly important one. They are 

 indispensable to the continuance of the higher 

 forms of life upon the earth. They may well 

 be called, in general, man's invisible friends; 

 for without them the earth would soon be 

 depopulated and lapse into what at first it 

 was a lifeless waste. 



