Dec. 2, 1908.] Agricultural Gazette of N.S. W. 1023 



The mixture found in the silo consists mainly of butyric and acetic 

 acids, but there occur also formic acid and some of the higher acids. 

 Formic acid and the higher acids are known to be the products of the 

 bacterial decomposition of cellulose, and as cellulose disappears during 

 ensilage one can safely attribute part of the volatile acid to organisms. 

 These decompositions are, however, quite secondaiy. 



The conversion of protein to non-protein. — Unlike the forriiation of 

 volatile acids, the decomposition of protein does not depend directly on the 

 living cell, for we find it going on in B, where the cells had been killed by 

 toluene. It does not, however, occur in C, where the enzymes had been 

 decomposed, and this change is therefore to be attributed to enzymes, which 

 can act not only during the life but also after the death of the cell. The 

 amount of change observed was — 



The quantity of protein decomposed is less when the cells are suddenly 

 killed by toluene than when they continue living for some time, but this is 

 quite consistent with the general facts of enzyme action. The killed cells 

 contain only the amount of enzyme present at the moment of death ; action 

 must therefore stop as soon as this has acted on the protein in its immediate 

 vicinity ; moreover, the toluene may retard its action. In A, on the other 

 hand, fresh quantities of enzyme can always be made so long as the cell 

 lives, and the presence of a little acid is known to be favourable to protein 

 hydrolysis. 



Further evidence of the presence of enzymes capable of deconi|)osing 

 protein was obtained by studying the changes in sterilized maize juice. 

 Some green maize was cut in October, at the time the silo was being filled. 

 It was pressed, and the juice, to which 2 per cent, of toluene was added, was 

 kept at 25° C ; after some time it was found to have undergone a consider- 

 able amount of hydrolysis, for there was a great increase in the compounds 

 decomposed by nitrous acid and in those precipitated by phosphotungstic 

 acid. Action has been more vigorous than in the last experiment, probably 

 ])ecause diffusion has gone on better. 



Total K 



N. liberated by nitrous acid... 



N. in phosphotungstic acid precipitate 



After being kept at 25°. 



As 2 i^er cent, of toluene was found to keep the juice sterile (for no growth 

 was obtained on inoculating a little into bouillon), this hydrolysis can only 



