BACTERIOLOGY OF SARDINES 207 



SESSIONAL PAPER No. 38a 



to acid, and profusely with much frothing to gas. In the glucose, lactose, 

 saccharose, mannite, raffinose, and arabinose tubes the Andrade indicator is 

 completely reduced within 24 hours, the reduction in the xylose, salicin and 

 aesculin tubes being slower. Compared with the other cultures described 

 herein, the rapid and violent action upon the carbohydrates is both distinctive 

 and characteristic, as also is the rapidity with which the Andrade indicator 

 is decolourized. The decolourized tubes when tested with methyl red show 

 decided alkalinity. The rapid reversion to an alkaline reaction is a point of 

 considerable interest. 



64a. — The fermentation reactions are identical with those of the above culture, 

 but a striking diiference, which may be but temporary however, has been 

 noted in the action upon the Andrade indicator. No reduction of the indi- 

 cator in any tubes was noted within 24 hours; in Y2 hours glucose, mannite, 

 arabinose, xylose and salicin had changed from the scarlet tint of the acid 

 reaction to a deep pink shade. In 7 days the glucose, arabinose, and xylose 

 tubes only were completely reduced giving an alkaline reaction to methyl red. 



I have as yet no explanation to offer regarding this apparent selective action 

 towards the Andrade indicator; the inoculations were made at the same time, 

 the same amount of the respective peptone broth cultures being added as the 

 inoculum,* such broth cultures being the same age, and all medium used of 

 the same standard stock. 



In this connection it may be of interest to mention that for some months I have 

 been experimenting with Congo red as an indicator in connection with routine 

 water analyses for the colon group; these experiments are as yet not suffi- 

 ciently complete for publication; I have used this indicator in sugar broths as 

 a confirmatory test and find that the strains 64 and 64a exhibit again, as in 

 the Andrade indicator, a selective action. 



Glucose. Lactose. Saccharose. Mannite. Dulcite. 



++ ++ ++ ++ 



Adonit. Raffinose. Arabinose. Xylose. Salicin. 



++ ++ ++ ++ : 



Aesculin. Glycerine. Inulin. 

 + + +=+= + + 



++ = acid and gas. 

 +•= acid. 



