330 



THE ROTHAMSTED EXPERIMENTS. 



No real 

 loss of 

 nitrogen. 



Experi- 

 ments with 

 sheep. 



amount of nitrogen accounted for was again less with direct 

 determination than by calculation from urea. 



In the case of the pig having the low-in-nitrogen barley- 

 meal and bran, there was, over the ten-day period, a loss indi- 

 cated of 7.16 per cent of nitrogen with direct determination, 

 and of only 4.90 per cent when the nitrogen was calculated 

 from the urea. In this case, therefore, there was again less 

 loss of nitrogen by calculation from urea than by direct 

 determination. Lastly, over the five-day period there was, 

 with the barley-meal and bran, a gain of nitrogen indicated of 

 7.76 per cent with direct determination of nitrogen in the 

 urine, and of 11.02 per cent when calculated from the urea. 

 In both cases, therefore, there was more nitrogen accounted 

 for by calculation from urea than by direct determination. 



These results obtained in 1862 show, therefore, with the 

 beans and bran, a slight gain over the ten days, and a slight 

 loss over the five days. On the other hand, with the barley 

 and bran there was a comparatively small loss over the ten 

 days, and a somewhat greater gain over the five days. 



When the fact that there was a much greater variation in 

 the amounts of the daily voidings. than in those of the food 

 daily consumed, and also the uncertainty in the estimation of 

 the proper increase of the animals over short periods and of 

 the nitrogen in it, are taken into account, these results must 

 be admitted to afford no evidence of any real loss to the 

 manure of the nitrogen of the food beyond that in the increase 

 and in the excrements. 



The next results to consider were obtained at Kothamsted 

 in 1861 with sheep. There were four pens with five sheep in 

 each. Besides the determination of the total dry matter, ash, 

 and nitrogen, in the food and in the excrements, one special 

 object was to determine what proportion of the cellulose of 

 the food was digested, and whether more or less was so 

 utilised according to the character of the foods given with it. 

 Accordingly, foods containing a comparatively large amount 

 of cellulose were selected, as under : — 



Food used. Pen 1. Meadow hay-chaff alone ad libitum. 



it 2. 1 lb. of ground beans per head per day, and meadow hay-chaff 



ad libitum. 

 u 3. 1 lb. of ground barley per head per day, and meadow hay-chaff 



ad libitum. 

 ii 4. About 6| oz. of ground beans, and about 3 J oz. of linseed-oil, 



per head per day, and meadow hay-chaff ad libitum. 



In Pen 4 the object was to give an amount of beans con- 

 taining the same quantity of nitrogen as the barley of Pen 3, 

 and then to make up the deficiency of starch in the smaller 



