1911.] 



Decomposition of Organic Compounds. 



269 



or outer fluid an E.M.F. might be developed, due to the variation of the 

 concentration of the sulphuric acid on either side of the diaphragm, and to 

 avoid this effect the cane sugar was added in the crystalline form. Following 

 the addition of the sugar an E.M.F. was produced amounting only to 

 002 volt, the sugar and sulphuric acid being zincative. Testing with 

 Fehling's solution showed that hydrolysis had taken place. 



The small voltage developed when cane sugar is hydrolysed by dilute 

 H2SO4 was further confirmed by adding the sugar as a thick syrup. In this 

 case a battery of five cells in series was arranged, the temperature of the cells 

 being 26° C. The syrup was added as quickly as possible to the cells, and 

 readings taken at once. From this battery an E.M.F. of 0*1 volt was 

 developed almost immediately, and too quickly to construct a curve showing 

 the times of development of the E.M.F. This method, however, is useful in 

 showing how the hydrolysis proceeds and the speed with which this reaction 

 dies away. 



Bacteria. 



I may now briefly refer to some experiments which were made with certain 

 species of bacteria. Pure cultures of Bacillus coli communis, B. flworescens, 

 B. violaceus, and Sarcina lutca were obtained from Dr. Krai, and, after 

 sterilisation as previously described, inoculations were made from each of 

 these micro-organisms upon nutrient solutions in the boiling tubes. The 

 solution used was a modification of the well-known Pasteur's solution, viz. : — 

 Potassium phosphate 2 



Calcium phosphate 2 



Magnesium sulphate 0'2 



Ammonium tartrate 10 



Asparagine - 5 



Water 1000 



B. coli communis flourished readily in this medium and proved to be an 

 excellent subject for the investigation. At 30° C. this organism, when grown 

 in the above solution, developed an E.M.F. recorded by the galvanometer as 

 0'308 volt. Using the same solution, but replacing the asparagine with 

 0'2-per-cent. starch, it gave rise to a voltage of - 349. At 20° C. the voltage 

 recorded was - 534 



In the case of B. violaceus, B. fluorescens, and Sarcina lutea no E.M.F. was 

 produced, these organisms causing no deflections of the galvanometer, either 

 at 30° C. or at 20° C. It was found that the medium employed was unsuit- 

 able for the growth of these bacteria, and they had quite failed to develop 

 under these conditions. 



