1024 Agriculturcd Gazette of N.S. W.. [Dec. 2, 1908. 



be attributed to enzymes. It is therefore evident that the inai/.e put into 

 the silo contained enzymes caj)al)le of hydrolysini^ tlie ])i-otein of the cell even 

 after the cell is dead. 



The change that has gone on in the silo clearly indicates that such a 

 hydrolysis has actually taken place, and is to he i-egarded as the primai-y 

 cause of the decomposition of protein dining rtisilagr. In the first placp, 

 the average general grouping of the nitrogen compounds in silage (seep. iO"21) 

 is much the same as that in the hydrolysecJ maize juice just refen-ed to; 

 nitrous acid liberated 55i per cent, of the total nitrogen in each case, and 

 phosphotungstic acid precipitated 37 and 33 per cent, respectively. In the 

 second place, typical ])n)(lucts of proteolysis occur in the silo. \\ hen pi-otein 

 is hydrolysed by tryptic enzymes the j)roducts include mono- and di-amino 

 acids (lysin, histidin, ifec). When nucleoproteins aj-e hydrolysed the purin 

 bases are obtained in addition. All these compounds are found in silage. 



it would not, however, be correct to ascribe the whole change to enzymes. 

 The organisms present are not without action on the nitrogen compounds, 

 and certain bodies — e.g., amines characteristic of bacterial action — are found 

 in tli(^ silo. But tlie bacterial changes a})pear to be secondaiv, and not an 

 essential jiart of the process. 



The hifliience of Free Oxygen on the Process. — The effect of allowing free 

 oxygen to have access to the maize in E (see p. 1022) was to alter the jjioduct 

 completely. There was a great development of Penicilliuin, which did not 

 appear when air was excluded. The mass became black and had a musty 

 smell ; it was alkaline and appeared to be free from acetates and butyrates ; 

 there had been an increase in the amount of protein, indicating that some 

 had been formed from the simpler non-})rotein material, presumably by the 



It will be remembered that in A and B, where air was excluded, the 

 protein had decreased 25 and 11 per cent, respectively, whilst here it has 

 increased 21 per cent. 



The change in the mm-protein substances was also .shown (lii-cctly by 

 detei-mining the amount of nitrogen liberated by nitrous acid. In the case 

 of good silage juice, more than 40 jjer cent, of the total nitrogen is set free 

 by this reagent ; while only 7 per cent, is liberated from juice e.xpressed from 

 the black, alkaline, mouldy layers found at the top of the silo, stretching 



^ 55 per cent, was the mean amount obtained from silage juice: the actual amount, 

 however, \aried considerably in (bti'erent samples from 3S per cent, to about 65 per cent. 



