A. Amos and H. E. Woodman 357 



Such features may be regarded as the chemical evidence of tipoihng, the 

 volatile bases having made their appearance as a result of the destruction 

 of amino acids. In the production of good silage, the main changes 

 aflecting the nitrogenous constituents are probably brought about by 

 proteolytic enzymes and an investigation of the material reveals a high 

 ratio of amino acids to volatile bases. The rotting of silage is evidenced 

 by a low ratio. The ratio in the case of bag 7 silage affords evidence 

 of the slight degree of spoiling which actually did occur in this bag. 

 A further ilhi.stration is seen in the figures already given for the titration 

 of the extract of the spoilt silage samjjle from the top of silo II. Here 

 the volatile bases are actually present in excess of the amino acids, the 

 ratio of amino acids to bases being roughly 1 : 1-6. 



In bags I, 2 and 3, where large quantities of juice were lost by 

 drainage, there were appreciable losses of crude protein, probably in 

 the form of "amides" dissolved in the juice. In bags 4, 5, G and 7, 

 where little or no juice was lost by drainage, only small changes in the 

 crude protein constituent were recorded. The slight gain of protein in 

 bags 4 and 5 arose probably from experimental error (difficulty of 

 accurate samphng, etc.). It may safely be assumed that if silage can be 

 made without excessive drainage from the silo, then the loss of crude 

 protein will be small. A twofold problem awaits satisfactory solution 

 if the practice of ensilage is to develop on a sound economical basis: 

 1. The prevention of excessive drainage from the silo. "2. The possible 

 utilisation of silage juice in feeding. Both these questions are receiving 

 attention at the present time. 



In every case the crude protein digestibility of the green oats and 

 tares (as determined in vitro) suffered a slight depression as a result of 

 ensilage. A study of the data points to the probability that the de- 

 pression of protein digestibihty is greatest where large losses of the easily 

 assimilated "amides" occur as a result of drainage. Where spoiling 

 occurs, as in bag 8, the decrease in protein digestibility may be con- 

 siderable. 



III. Changes suffered by the Ether Extract. 



In all the bags, with the exception of bags 7 and 8, the amount of 

 ether soluble material was augmented as a result of the changes under- 

 gone by the green forage during ensilage. The increase was very variable 

 in amount and apparently bore no relation to the percentage loss of 

 nitrogen-free extractives. Thus, in bag 4, where about 12 per cent, of 

 the nitrogen-free extractives disappeared, there was a 13 per cent. 



