Aug. 15, 1921 
Bacteriology and Chemistry of Different Silages 
771 
CHEMICAL METHODS 
From the sample of silage the juice was expressed and used for the 
chemical analysis. 
Total acidity. —Ten cc. of juice were diluted with 990 cc. of distilled 
water and titrated with N/10 barium-hydroxid solution, using phenolpli- 
thalein as an indicator. 
Volatile acidity. —Twenty-five cc. of juice were subjected to steam 
distillation under reduced pressure. One liter of distillate was secured 
and titrated immediately with N/10 barium hydroxid, using plienol- 
plithalein as an indicator. Experiences in other investigations have 
established the efficiency of this method (5). 
Amino nitrogen. —The amino nitrogen was determined by the use of 
the Van Slyke apparatus ( 20 ). 
Ammonia nitrogen. —The ammonia was determined by the use of 
Folin’s method, using 25 cc. of juice and aerating for at least eight hours. 
Albuminoid nitrogen . 1 —This was run on the first and last sample 
of most of the silage. It was determined by Stutzer’s method. 
Total nitrogen . 1 —The total nitrogen was determined by the Kjel- 
dalil method. 
Moisture. —One thousand gin. of a well-mixed sample of the silage 
were placed in an air-drying oven for at least three days. 
El ELD EXPERIMENTS 
Three separate field experiments were performed: 
I. Canada field peas and oats, 1918. 
II. Canada field peas and oats, 1919. 
III. Corn in comparison with corn and soybean mixture, 1918. 
EXPERIMENT I. CANADA FIELD PEA AND OAT SILAGE, 1918 
The crop of oats and peas was seeded May 6 and stored in the silo 
July 17. The oats were in the milk stage of growth and the peas were 
well formed in the pod. The fresh green mixture at the time of ensiling 
contained, on the average, 18.4 per cent peas. On account of the 
extremely dry weather for the two weeks just previous to harvesting, 
the moisture content was rather low, being only 70 per cent. The 
silage mixture kept very well -and was eaten with relish by the cows on 
the experiment. Feeding was not begun until August 8 so as not to 
interfere with the method of securing samples. The results of the bac¬ 
teriological examination are given in Table I. 
1 The analytical work of determining the total and albuminoid nitrogen was done by Mr. Walter Thomas, 
Assistant Chemist of the Pennsylvania Agricultural Experiment Station. 
