32 MORPHOLOGY OF THE BACTERIA.' 



by Warming and Giard. They are found in va- 

 rious media — in sea-water, in hot sulphur springs, 

 in fresh water containing animal or vegetable mat- 

 ter in a state of putrefaction. They appear some- 

 times upon bread, meats, and in general upon 

 cooked food placed in a humid atmosphere. The 

 different colors which they present are red, yel- 

 low, orange, and blue. It is probably to anal- 

 ogous organisms that we must attribute the blue 

 color presented by pus under certain circum- 

 stances, the green and blue color studied by 

 M. Chalvet, and the orange-yellow, bright red, 

 and blue colors observed by C. Eberth in perspi- 

 ration. 



In Norway, red bacteria appear in summer in 

 such masses that the borders of the sea are some- 

 times colored of an intense red (Warming). 



Movement. — The bacteria are met in two dif- 

 ferent states. They are active or motionless ; but 

 it is now well settled for the greater number that 

 the same species may present itself sometimes in 

 a state of repose, sometimes in a state of move- 

 ment. 



The movements of the bacteria are of two kinds, 

 — a movement of the corpuscle upon itself and a 

 movement of translation. The first is sometimes 

 nothing more than a molecular or brownien move- 

 ment, which occurs in the smallest forms. But at 

 other times it is more extended, and consists in a 

 movement of rotation round the axis, or a bend- 

 ing of the body. This flexibility is, above all, 



