40 MICROBIOLOGY 



In practical bacteriological analyses, usually no attempt 

 is made to identify all the species present but to ascertain 

 the number of individual bacteria or the presence of bac- 

 teria belonging to groups known to contain species that are 

 of special significance. In examining organs for purposes 

 of diagnosis the effort is to find the specific organisms pres- 

 ent and to isolate and identify them. It is also desirable to 

 ascertain when possible other species if they are present in 

 the tissues. Although the known pathogenic bacteria have 

 their properties sufficiently described to make their identifica- 

 tion possible, there are many bacteria that can live for a 

 certain time on tissues and which may appear to have a 

 causal relation to the lesions but are not so readily identi- 

 fied. These bacteria when found should be either identified, 

 placed in a definite group, or failing in these, described as a 

 new species. 



DESCRIPTIVE CHART SOCIETY OF AMERICAN 

 BACTERIOLOGISTS * 



Prepared by F. D. Chester, F. P. Gorham, Erwin F. Smith, Com- 

 mittee on Methods of Identification of Bacterial Species. En- 

 dorsed by the Society for general use at the Annual Meeting, 

 Dec. 31, 1907. 



GLOSSARY OF TERMS. 



AGAR HANGING BLOCK, a small block of nutrient agar cut from 

 a poured plate, and placed on a cover-glass, the surface next 

 the glass having been first touched with a loop from a young 

 fluid culture or with a dilution from the same. It is examined 

 upside down, the same as a hanging drop. 



AMEBOID, assuming various shapes like an ameba. 



AMORPHOUS, without visible differentiation in structure. 



ARBORESCENT, a branched', tree-like growth. 



BEADED, in stab or stroke, disjointed or semi-confluent colonies 

 along the line of inoculation. 



BRIEF, a few days, a week. 



* This chart can be procured from the Secretary of the Soc. of 

 Am. Bacteriologists. It is very convenient for recording descriptive 

 characters of bacteria. 



