8 



chloric acid must also exist, especially in the spring just after the 

 application of the manures. The acid arises from the ammonium 

 salts, which are split up by certain micro-fungi abundant in the soil 

 of these plots, the ammonia being utilised by the fungus and the acid 

 set free. Year by year this soluble acid has attacked the normal 

 calcium humate of the soil, setting free the humic acid, which being 

 very sparingly soluble has accumulated. Owing to their acid 

 condition nitrification has almost ceased in these soils, the bacteria 

 causing the change being only occasionally found, so that the grasses 

 and other plants living on the plots must be feeding directly on the 

 ammonium salts. The poor growth of plants on acid soils may be 

 attributed to the displacement in the soil of the normal bacteria by a 

 fungus flora which competes with the crop for any manure or other 

 plant food in the soil. 



'' The Nitrogen Compounds of the Fundamental Rocks" by 

 A. D. Hall and N. H J. Miller, Jour. Agric. Science, Vol. II., 

 Part 4, 1908. This paper continues the study of the carbon and 

 nitrogen compounds which exist in many rocks taken from great 

 depths beyond the reach of weathering. It is shown that when sub- 

 jected to the action of soil bacteria such compounds are attacked, 

 but they yield nitrate so slowly that in all probability some of the 

 nitrogen found in soils is not of recent origin but has come from 

 the original rock out of which the soil was formed. Ammonia and 

 nitrates were found in all the rocks. 



" The Chemical Changes taking place during the Ensilage of 

 Maize" by E. J. Russell, Jour. Agric. Science, Vol. II., Part 4, 

 1908. The conversion of green crops into silage is not an ordinary 

 feature of English farming, but it can be and often is practised in 

 certain not unusual circumstances. When the season is too wet for 

 making hay the grass can be made into silage. On many of the light 

 chalky soils of the South-Eastern Counties good crops of green 

 maize can be obtained even when roots have failed, but any of the 

 crop that has not been fed off by the end of September must be made 

 into silage or it will not keep. The extension of the area under 

 green leguminous crops would be considerably simplified if the green 

 material could be profitably converted into silage. The problem is 

 therefore of considerable importance, and the investigations begun 

 at Wye were finished here. The object of the enquiry was to trace 

 the changes taking place in the silo, to ascertain which are the 

 fundamental changes that would go on in any silo however perfect, 

 and which are the secondary changes that come into play in an 

 ordinary imperfect silo. 



The course of the change was found to be as follows : The maize 

 cells are still living when put into the silo, and continue their 

 respiration, using up sugar with production of carbonic acid, acetic 



