EXAMINATION OP CULTURES 



115 



gelatin the same observation should be made and also 

 whether liquefaction has taken place and if so to what ex- 

 tent and in what form. For this purpose, Chester has intro- 

 duced a terminology in descriptive bacteriology which has 

 the advantage of being definite and- concise, while at the 

 same time it is sufficiently elastic to fit the varying forms of 

 growth. It applies to the surface growth, to the growth 

 along the needle track in the depth of the media, and to 

 colonies on plate cultures. 

 1. Surface elevation. General character of surface growth as a 



whole. 

 Flat: thin, leafy, spreading over the surface. 



Fig. 40. Characters of 

 growth in depth of me- 

 dia: 1, filiform; 2, bead- 

 ed; 3, tuberculate- 

 echinulate; 4, arbores- 

 cent; 5, villous. 



-co] 



T 



Fig. 41. Types of 

 liquefaction in gelatin 

 stab cultures: 1, crateri- 

 form; 2, napiform; 3, 

 saccate; 4, infundibuli- 

 form; 5, stratiform. 







Effused: spread over the surface as a thin, veilly layer, more 



delicate than the preceding. 



Raised: growth thick, with abrupt terraced edges. 

 Convex: surface the segment of a circle, but very flatly convex. 

 Pulvinate: surface the segment of a circle, but decidedly convex. 

 Capitate: surface hemispherical. 



2. Gelatin stab cultures. Nonliquefying line of puncture. 

 Filiform: uniform growth, without special character. 

 Nodose: consisting of closely aggregated colonies. 

 Beaded: consisting of loosely placed or disjointed colonies. 

 Papillate: beset with papillate extensions. 

 Echinate: beset with acicular extensions. 

 1 7 illous: beset with short, undivided, hairlike extensions. 



