APPENDIX. 



EXAMINATION OF THE WATER OF THE SCHUYLKILL RIVER FOR THE COLON BACILLUS OF ESCHERICH. 



By Dr. Olmstkad, Jssislanl Bad riologist, Lahoralorij of Hygiene, University of PeunsyUaii ia. 



Advantage was takeii of the fact that inauy forms of water bacteria will not grow at the 

 temperature of 37° C. Thirty samples of water were examined during February and the early 

 part of March of this year. 



The tap was opened, and after the water had been running au hour SO cc. were collected iu a 

 sterilized Erlenmeyer's flask, containing 20 cc. of sterilized alkaline sugar bouillon, quadruple the 

 ordinary strength. The mixture, after the addition of the sample of water, was composed of — 



Sodium chloride grains.. 0. 4 



Peptoue do 0. 8 



Liebig's extract of me.at do 0. 15 



Glucose do 1.5 



Sterilized water cubic eeutiraeter.. 20 



Water for examination do 80 



Caustic solution sufficient to make alkaline. 



The fla.sk was then placed in a thermostat and kept at a temperature of 37° C. for twenty-four 

 liours, when, as a rule, there was a prolific growth in the flask. A set of agar-agar plates was 

 made from this growth and placed in the thermostat. In about tweuty-flve samjjles pure cultures 

 of only one organism were obtained on the plates; in the other five samples two, or perhaps three, 

 varieties of germs were present. Only those with a morphology similar to the colon bacillus were 

 taken for further examination. 



For identification the following media were used: 



1. Agar-agar. 



2. Potato. 



3. Gelatiu, stick and plate. 



4. Peptone, for indol and motility. 



5. Litmus milk. 



6. Sugar bouillon in Eiuhorn's fermentation tubes, as recommended by Smith. 



The growths were all compared with those of a typical culture of colon bacillus obtained from 

 the intestinal tract. The germs found may be divided into four groups: 



Group I. — Iu this are placed bacilli obtained from three specimens whose morphology and 

 cultural ])eculiarities resemble in every particular those "f the colon bacillus and, we believe, are 

 identical with it. Thus they formed a whitish band-like growth on agar-agar; a yellowi.sh, slightly 

 raised growth on potato; reddened and coagulated lituuis milk; produced indol ; caused fermen- 

 tation of glucose in bouillon. The colonies in gelatin were of two principal varieties, the deep 

 ones being round, yellowish brown, finely granular, with some circular markings. The superficial 



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