632 LABORATORY EXERCISES 



I Gelatin liquefied. 



2 , Gelatin not liquefied. 



0.1 Acid and gas from dextrose. 



0.2 Acid without gas from dextrose. 



0.3 No acid from dextrose. 



0.4 No growth with dextrose. 



o.oi Acid and gas from lactose. 



o. 02 Acid without gas from lactose. 



o. 03 No acid from lactose. 



0.04 No growth with lactose. 



o. 001 Acid and gas from saccharose. 



o. 002 Acid without gas from saccharose. 



o. 003 No acid from saccharose. 



0.004 No growth with saccharose. 



o.oooi Nitrates reduced with evolution of gas. 



o. 0002 Nitrates not reduced. 



0,0003 Nitrates reduced without gas formation. 



o . ooooi Fluorescent. 



o. 00002 Violet chromogens. 



o . 00003 Blue chromogens. 



o . 00004 Green chromogens. 



0.00005 Yellow chromogens. 



0.00006 Orange chromogens. 



o. 00007 Red chromogens. 



0.00008 Brown chromogens. 



o . 00009 Pink chromogens. 



o . 00000 Non-chromogens. 



o. oooooi Diastatic action on potato starch (strong). 



o. 000002 Diastatic action on potato starch (feeble). 



o. 000003 Diastatic action on potato starch (absent). 



o. ooooooi Acid and gas from glycerin. 



0.0000002 Acid without gas from glycerin. 



o . 0000003 No acid from glycerin. 



o . 0000004 No growth with glycerin. 



The genus, according to the system of Migula, is given its proper symbol which 

 precedes the member thus: According to the above the symbol of Bacillus coli 

 would be B. 222.111102 and of Pseudomonas campeslris Ps. 211.333151. This will 

 be found useful as a quick method of showing close relationships inside the genus, 

 but is not a sufficient characterization of any organism. The descriptive chart of 

 the Society of American Bacteriologists of which the above decimal system forms 

 a part will be found useful in the detailed systematic study of the bacteria. It was 

 prepared by F. D. Chester, F. P. Gorham and Erwin F. Smith, appointed as a 

 committee on methods of identification of bacterial species. Their report was 

 endorsed by the society at the annual meeting, December, 1907. 



