Slime Moulds, Bacteria, and Yeasts. 259 



therefore, live upon materials already organized, or they 

 must utilize some source of energy other than the sunlight 

 for the construction of their food. Most bacteria have 

 adopted the former course, and obtain their sustenance from 







S?ilsWJB-'--''.~s'-.^" '^•'S .■■■•■^■'1 



■'-(■in.-' 



Fig. 134. 



<?, bacilli of typhoid fever; /, bacilli of chicken cholera; ^, bacilli of splenic fever; 

 A, spirillum of recurrent fever, and red blood corpuscles. Photomicrographs 

 X 740. After GUNTHER. 



the bodies or products of plants and animals. Others, 

 however, are able to induce the oxidation of compounds of 

 nitrogen, sulphur, iron, etc., and appropriate the heat thus 

 produced for the fixation of carbon from carbon dioxide, 

 much as green plants do by means of the sunlight. To 



