ORGANISMS OF SANITARY SIGNIFICANCE ON GRAINS 217 



This set of cultures of B. coli was further compared with the 

 intestinal organisms by a study of the staining relations, with the 

 result that the organisms were found to react toward dyes in the same 

 manner, with the usual staining methods as well as by Gram's method. 



COMPARISON OF STREPTOCOCCUS PYOGENES FROM GRAIN 

 AND FROM INTESTINAL SOURCES. 



Having shown the constant occurrence of streptococci, their com- 

 parison with intestinal organisms of the same genus is of interest. 



The form of most significance in sanitary work is Strept. pyogenes, 

 the ''sewage streptococcus." This organism presents the following 

 characteristics : 



Form. Coccus, IA* in diameter. 



Grouping. Occurs in short chains, often in pairs. 



Motilit y . Non-motile . 



Spore formation. None. 



Gelatin plate. Small colonies, similar to those on agar; no liquefaction. 



Gelatin stab. Nail growth, apparently made up of isolated colonies; very slight 

 spreading on surface. 



Agar plate. Colonies small; under low power somewhat irregular in form; 

 edges smooth. 



Agar streak. Faint dotted growth in 24 hours. 



Broth. Faint turbidity and perceptible sediment in 18 hours; on shaking, sedi- 

 ment rises in spiral. 



Litmus milk. Twelve hours: slightly acid; litmus slightly decolorized; 18 hours, 

 strongly acid; 36 hours, coagulated. 



Potato. Invisible or hardly perceptible white growth after three days. 



Dextrose broth. Eighteen hours: strongly acid; no gas; sediment and slight 

 turbidity in both arms. 



Saccharose broth. Eighteen hours: sediment and turbidity, but no evidence 

 of change of sugar. 



Lactose broth. Same as dextrose broth. 



Maltose broth. Same as dextrose broth. 



Litmus lactose agar plate. Twelve hours: litmus reddened; colonies small 

 with pink tint as if colored by litmus. 



Dunham's solution. Apparently no growth; no indol produced. 



Anaerobic agar streak. Dotted growth similar to aerobic, but rather less strong. 



The cultures isolated from the grains were compared side by side 

 with a set of streptococci isolated directly from feces. Only those 

 organisms showing typical morphological appearance in stained prepa- 

 ration were used in this comparison. Three cultures of Strept. pyo- 

 genes, eight from rye, six from oats, three from buckwheat, one from 

 wheat, and eight cultures from feces all proved to be alike in their cul- 



