246 CROPS. XI. 



% 



Proteids ... ... 11-80 



Ash ... ... 7-62 



Ether extract ... 1-86 



Woody tissue ... 26-40 



Non-nitrogenous extract 52-32 



100-00 



was placed in a large vessel provided with thermometer 

 and delivery tube. In 24 hours the temperature rose several 

 degrees ; during four weeks a slow current of carbon dioxide 

 (64 %) and nitrogen (36 %) was evolved. 



The grass at this point had the composition : 



% 

 Proteids ... ... 9'13 



Ash ... ... 8-14 



Ether extract ... 3-24 



Woody tissue ... 31-36 



Non-nitrogeous extract ... 48-13 



100-00 



It had a pleasant hay-like odour. Many moulds, bacteria, 

 and micrococci were observed. The increase in the ether ex- 

 tract is attributed to organic acids formed from the carbo- 

 hydrates. 



No doubt such changes as above described take place during 

 the process of hay-making ; but usually they can only proceed 

 to a very limited extent, owing to the desiccation of the grass 

 by sun and wind. 



When the partially dried grass is collected in stacks or barns, 

 however, further desiccation is almost prevented, and the pro- 

 cesses of fermentation recommence. If the hay still contain 

 much moisture these processes proceed so rapidly that the 

 very limited circulation of air in the stack does not carry the 

 heat away as fast as it is produced, the temperature rises, fer- 

 mentation is thereby favoured, and the temperature gets higher 

 and higher. 



While most organisms are killed by a temperature about 

 60, it has been shown that certain bacteria present in surface 



