322 THK I'KESENCE, TVl'E, AND POSSIBLE SIGNIFICANCE OF LACTOSE-FEKMENTINO HACILLI 



orf,'!inisms met with in these experiments, the term B. coJi was only applied to Escherich's 

 or^'iviiisnis. All bacilli f,'ivint,' (lifforeiit reactions in any permanent test were looked upon 

 as different species, aii<l different names and nnuilicrs were given to them. 



Further, by usinj; the two sugars, saccharose and dulcit, one was able to adopt 

 MacConkey's method of dividing all lactose fermenters into the following four groups: — 



Group I Fcrmuuts neither saccharose nor dulcit 



,, 11 ... ... „ dulcit liut uot saccharose 



,, 111 „ dulcit and Sitccharosc 



„ IV ... ... „ saccharose but not dulcit 



Tlie following few experiments were carried out to estimate the varieties of fajcal 

 organisms present in river and well-water, etc. Numbers were given to organisms that 

 did not correspond in their reactions to any named bacillus, and, as mentioned, the term 

 li. coli was applied only to Escherich's organism. 



In addition to being put into the media described above, the organisms isolated were 

 also inoculated into glucose, litmus milk, and inosit, and although the results obtained 

 with these media do not figure in the tables, the reactions were made use of in attempting 

 to identify any doubtful organism. 



The sign + indicates the formation of acid and gas. 



The sign — indicates a negative reaction as regards the presence of acid and gas, 

 and an asterisk indicates that the bacillus is an unnamed one. 



Experiment I. — Date, July 16, 1910. Local rainfall, nil. 



Sample taken from the Blue Nile at a distance of two metres from the river bank. 



The river had been rising steadily for a period of three weeks owing to the rainfall 

 up-country. 



Temperature of water, 27' C. 



(a) Total colonies on agar at 37 = 700 per 1 c.c. 



(6) Fascal bacilli present in '5 c.c. 



(f) Sporogenes milk test -f in 20 c.c. 



Qroup I, 1 



Group n, 7 



Group III, 2 



