186 



A COURSE ON ZOOLOGY. 



multiply so rapidly that they often render the blood of 

 animals infected with them thick and muddy. At the 

 same time they deprive the blood of oxygen, and it 

 becomes black like soot, from which the French give to 

 the disease the name charbon (coal). 



FIG. 114. 



DIFFERENT KINDS OF BACTERIA (mostly after Koch). A, micrococci in drink- 

 ing-water; B, in splenic fever; C, in cholera (Koch) ; D, from surface of 

 water : E, in splenic fever (in thread-form, and with incipient spores) ; F, 

 spirillum, from putrefaction ; G, spirochsete, from the teeth ; H, in relaps- 

 ing fever, from blood ; I, different forms of cholera microbe (Koch). 



It is a special property of microbes to develop and 

 multiply with great rapidity. If a few individuals, 

 either bacteria or vibrios, be placed in a clear liquid 

 adapted for their development, in a short time it be- 

 comes clouded, and a deposit forms. This deposit is 

 composed entirely of microbes, so great is the number 



