798 



SCIENCE 



[N. S. Vol. XXVI. No. 675 



streptococci from various sources by compari- . 

 son of fermentative power encouraged us to 

 hope for results. 



With this end in view, fifty-two cultures of 

 dextrose-fermenting organisms were isolated 

 from human feces. The procedure in all cases 

 consisted in the inoculation, with a small por- 

 tion of the material, of a fermentation tube 

 from which litmus-lactose-agar plates were 

 made on the first appearance of gas. Of the 

 52 cultures thus isolated, 5 failed to give a 

 typical reaction in milk, 7 failed to reduce 

 nitrates, 6 formed no indol, and 16 liquefied 

 gelatin. Thirty-one of the 52 cultures proved 

 to be B. coli, as determined by the five tests 

 mentioned above, and 25 of them were used for 

 comparative tests in various carbohydrates. 



After the work with the intestinal B. coli 

 was completed the attempt was made (in the 

 summer of 1907) to secure similar forms from 

 growing grains. Heads of grains and grasses 

 of various sorts were collected from fields in 

 eastern Massachusetts and brought to the 

 laboratory in sterile test-tubes. Portions of 

 perhaps an inch in length were placed in 

 dextrose fermentation tubes and when gas 

 formation began litmus-lactose-agar plates 

 were inoculated. One hundred and seventy- 

 eight samples of grain, however, showed gas 

 in the dextrose tube only 50 times; and 40 

 samples of grasses failed to show gas at all. 

 Of the 50 samples plated on litmus-lactose- 

 agar only three showed red colonies, and of the 

 organisms isolated all three liquefied gelatin. 

 Time was not available to pursue this in- 

 vestigation further. It seemed to us, however, 

 that our inability to isolate B. coli from 218 

 samples of grains and grasses was in itself of 

 some interest. The experience corresponds 

 with that of Laurent," and Klein, and Hous- 

 ton,* but not with the results of Prescott 

 {L c), and Papasotiriu." 



The results obtained with the intestinal B. 



Government Board for 1902-3; Report of the 

 Medical Officer to the Local Government Board 

 for 1903-4. 



'An7i. de I'Inst. Pasteur, 1899, 13. 



' Report of the Medical Officer to the Local 

 Government Board for 1899-1900. 



" Archiv fiir Hygiene, XLI., 204. 



coli may perhaps be of some assistance to 

 workers along similar lines. Each of the 25 

 cultures studied was inoculated into 12 differ- 

 ent fermentable media in fermentation tubes. 

 The basis of the medium was in each case 

 nutrient broth, to which 1 per cent, of the sub- 

 stance to be tested had been added, steriliza- 

 tion being carried out at 100° on three suc- 

 cessive days. Two monosaccharides, dextrose 

 and galactose; 5 polysaccharides, lactose, mal- 

 tose, xylose, saccharose and raffinose; two 

 alcohols, dulcite and mannite, two starch-like 

 bodies, dextrin and inulin, and one albumi- 

 noid, nutrose — were used as substances to be 

 fermented. 



ACID PKODUCTION BY B. COLI (INTESTINAL) 



Acidity in terms of c.o. N/20- NaOH per ex. of 

 the culture medium. 72 hours' incubation 



After 72 hours' incubation at 37° the oc- 

 currence of gas formation was observed and 

 the reaction of the medium was determined by 

 titration against iV/20 NaOH. Uninoculated 

 tubes were, of course, titrated in parallel as 

 controls. The general results of the titrations 

 are indicated in the table below, the acidity in 



