i9i i.] Summary of Agricultural Experiments, 679 



transmission of rust from susceptible to immune varieties, and this may 

 afford an explanation of the eventual failure of some rust-resistant 

 varieties and of other obscure points connected with immunity. 



Heating of Hay Ricks (Biedermann's Zentralhlatt fur Agrikultur- 

 chemie, August, 191 1). — Analyses of heated hay from ricks having 

 temperatures of 85 0 C. and 95 0 C. (165 0 F. — 183 0 F.), and of normal 

 hay from the same ricks, showed that heating is accompanied by a 

 decrease in the content of the hay in pentosans and carbohydrates. 

 The following was the actual composition of the dry matter : — 



Heated Unheated 



hay. hay. 



Per cent. Per cent. 



Ash 9 '2 8 -4 



Protein 11-5 10 8 



Pentosans 20*6 24*0 



Crude fibre 35*4 31 '6 



Fat 3-1 2-0 



Carbohydrates 20'2 23*2 



The acidity produced by heating was found to be due principally to 

 formic acid. Samples of gas from the interior of a heated rick were 

 taken and found to consist of 7 per cent, carbonic acid gas, 12 '4 per 

 cent, oxygen, and 80 per cent, nitrogen. As the composition of the 

 atmosphere is about 20 per cent, oxygen and 80 per cent, nitrogen, it 

 would appear that in addition to forming carbonic acid gas, some of 

 the oxygen (o"6 per cent.) combines with the carbon remaining in the 

 hay. 



It has been suggested (see Journal, June, 1908, p. 221) that heating 

 is due to the action of bacteria, but the fact of the oxygen combining 

 with the hay would seem to indicate that it is due to oxidation. In 

 these experiments the number of bacteria found in the heated hay, 

 either by microscopic examination or by obtaining gelatine cultures of 

 the hay, was insufficient to account for the heating. Microscopic 

 examination of a stem of blackened hay revealed a normal epidermis 

 and a parenchymatous tissue with cell walls intact, so that bacteria 

 could not have found their way into the interior of the cells. It 

 appears therefore that the heating of hay cannot be ascribed to the 

 action of bacteria. 



Experiments in the laboratory seemed to confirm the opinion that 

 heating is due to oxidation. Tubes containing hay and filled with 

 oxygen were sealed up and heated, and the oxygen was found to 

 enter partly into combination with the hay, in addition to forming 

 carbonic acid gas. A greater resemblance to hay heated in the rick 

 was obtained from tests with grass dried in a vacuum, air-dried hay 

 having already been more or less oxidised. Further experiments 

 showed that the effect of oxygen on hay begins at about 33 0 C. (95 0 F.), 

 the production of carbonic acid gas, and the combination of oxygen 

 with the hay, taking place at this temperature; and the presence of 

 moisture was found greatly to influence this oxidation. A section of a 

 hay stem so treated could not be distinguished either under the micro- 

 scope or by analysis of dry matter from hay naturally heated in the 

 rick. 



Varieties of Wheat (Rept. on the Woburn Field Expts., Jour. Roy. 

 Agric. Soc, Vol. 71, 1910). — The varieties tested were sown in Novem- 

 ber, 1909, after a well-manured potato crop. The yields were as fol- 



