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Mr. E. C. Grey. Decompositio7i of 



this communication a series of experiments will be described wherein 

 the duration of each experiment was of this order, sincC; though these 

 results represent the average of several fermentation processes which occur 

 together, they have the value of indicating the manner in which the various 

 products of the fermentations vary with changes in the conditions of the 

 experiment and they give information as to the probable origin of succinic 

 acid in this particular fermentation. In Part III an experiment will be 

 described in which the several phases which characterise this bacterial 

 fermentation process have, to a certain extent, been separately studied. 



Bacteriological Technique. 



For the sake of future reference, and for present uniformity, it has been 

 thought best to employ only standard organisms. In these experiments the 

 B. coli Govvnmnis of the collection of the Institut Pasteur has been used. The 

 treatment of the organism prior to its mixture with the substance to be 

 fermented has also been made to conform to a uniform plan. In each case a 

 loopful taken from a growth on agar has been inoculated into beef bouillon and 

 the fluid incubated for 24 hours at 38° C. This culture has been used to 

 inoculate a series of Eoux bottles containing agar prepared after the manner 

 recommended by Dr. Martin. The technique of inoculating the bottles, as 

 well as for the subsequent removal of the growth, is practically that employed 

 by Dr. Salambini, of the Pasteur Institute. Instead of the saline solution 

 employed for the preparation of vaccines a solution of potassium sulphate or 

 mixture of this and magnesium sulphate is employed, as it is not desirable to 

 introduce the salt of any volatile acid such as hydrochloric acid into the 

 fermentation solution. The growth in the Eoux bottles has been allowed to 

 take place during 48 hours in each case. At the end of this period about 

 100 c.c. of sterile sulphate solution is introduced into each bottle. The con- 

 centration of the sulphate solution used depends upon the object of the 

 experiment. A very great variation in concentration is permissible. The 

 maximum decomposition of glucose obtained in a series of preliminary 

 experiments was found to occur with a concentration of potassium sulphate 

 equivalent to 3]Sr/40 K2SO4. With this concentration of potassium sulphate 

 in the fermentation solution 1 grm. of bacteria decomposed 40 grm. of glucose 

 in 48 hours. The only ion which it was found of value to add to the 

 potassium sulphate solution was magnesium. The addition of sulphate of 

 magnesium will increase the rate of fermentation by about 15 per cent. 

 With the exception of calcium, which the writer has found to be of benefit iu 

 the decomposition of sugar by B. coli communis, and which is present in 

 excess in these experiments, no other metallic ion nor any negative ion was 



