DESCRIPTION OF PLATES. 135 
nutritive base for several of these, and their pres- 
ence will be recognized by the bright color of the 
little gelatinous masses or stains produced by their 
agerevation. 
Micrococci abound in the pus from open wounds, 
and are also found in that drawn from closed ab- 
scesses of an acute character. Milk, pus, and 
perspiration are sometimes colored red or blue, in 
consequence of the presence of micrococci having 
these colors. 
Micrococci are liable to be mistaken for granu- 
lar matter of organic origin; but usually the mis- 
take is the other way, and organic or inorganic 
granules are mistaken for micrococci. The vibra- 
tory movement — Brownian movement —by which 
very minute particles suspended in a liquid are 
seen to be agitated, often leads to mistake by 
those who are unfamiliar with this molecular move- 
ment. Micrococci are also subject to this oscilla- 
tory motion, which should not be confounded with 
vital movements, in which the organism is visibly 
transported from place to place by virtue of some 
motive-power residing in its own organization, and 
independent of any currents in the fluid in which 
it is immersed. Independent vital movements of 
such a nature the micrococci do not exhibit; but 
many of the micro-organisms of the class to which 
they belong are endowed with movement, and 
may be seen swimming actively across the field 
of view, —some simply in right lines; others in 
a jerky, oscillatory way; others in a serpentine 
manner ; and still others in a spiral direction. 
