CHAPTER III. 



TAXONOMY. 



POINTS TO BE OBSERVED IN THE STUDY OF BACTERIA. 



The following scheme gives an idea of the points to be noted in the description of 

 an organism together with some of the more common descriptive terms. 



CULTURE CHARACTERS. 

 1. GELATIN PLATE: 



A. Surface colonies. 



a. Form: Punctiform, too small to be defined by naked eye; circular; oval; 

 irregular; fusiform; cochlate, twisted like a snail shell; amoeboid, very irregular like 

 changing forms of amoebae; conglomerate, an aggregation of colonies. 



b. Size, expressed in millimeters. 



c. Surface Elevation: flat; spreading; thin; raised, growth thick with abrupt, 

 terraced edges; convex, surface segment of a circle but very flatly convex; pulvinate, sur- 

 face the segment of a circle but decidedly convex; capitate, hemispherical; rough, irregular 

 elevations and depressions; contoured, like the undulating surface of a relief map; papil- 

 late, horn like projections; rugose, wrinkled; alveolate, depressions separated by thin 

 walls; pitted; sulcate, ridged or furrowed. 



d. Consistency: thin; membraneous, thin, dry, separating from medium; coria- 

 ceous, thick like leather or parchment; viscous, ropy; slimy ; gelatinous; brittle. 



e. Color: transparent; vitreous, transparent and colorless; oleaginous, trans- 

 parent and yellow, olive to linseed oil colored; resinous, transparent and brown, varnish 

 or resin colored; translucent; paraffinous, translucent and white, porcelaneous ; opales- 

 cent, translucent, grayish-white by reflected light, smoky-brown by transmitted 

 light; nacreous, translucent, grayish- white with pearly lustre; sebaceous, trans- 

 lucent, yellowish or grayish- white, tallowy; butijrous, translucent or yellow; 

 ceraceous, translucent and wax colored; opaque; cretaceous, opaque and white; 

 chalky, dull without lustre; glossy, shining; fluorescent; iridescent. 



f. Margin (To be determined by low power of microscope): entire; undulate; 

 repand; erase, finely eroded as if gnawed; lobed; articulate; laciniate, cut jaggedly into 

 deep narrow lobes; lacerate, cut variously into irregular segments' fimbricate, edge 

 bordered by slender processes thicker than hairs; ciliate, tufted; floccose, wooly, filaments 

 in fleecy masses; curled, filaments in locks or ringlets: filamentous, consisting of loosely 

 placed, interwoven filaments, not so dense as floccose. 



g. Internal structure (To be determined by microscope) : homogeneous, uniform 

 throughout; concentrically zoned; marmorated, traversed by veins as in some kinds of 

 marble, marbled; finely punctate; areolate, marked out with small spaces, reticulate; 

 moruloid, having the character of a morula, resembling a mulberry; segmented; finely 

 granular; coarsely granular; grained, as in lumber; curled, composed of twisted bundles 

 of parallel filaments as in locks or ringlets; floccose; filamentous. 



h. Change in Medium: consistency; color; odor. 



