ANNUAL REPORT, 1P29 363 



have been made from time to time, but without a definitely established! 

 basis of fact. 



The Station herd has been divided iinto two groups, one receiving grain 

 at the rate of one pound to four and one-half pounds of milk, 40 pounds 

 of silage and what hay they will clean up; the other group receiving grain 

 at the rate of one pound to two and one-haJf pouindis of milk, 25 pounds 

 of silage and what hay they will clean up. The cows are being carefully 

 observed, and the usual checks om live weight each month, milk production, 

 and the reproductive function, are being maintained. It is too soon to 

 draw definite conclusions from the trial. The plan is to contimue it for 

 at least three lactation periods of all the cows. 



The Chemical Composition of Grass frpm Plojts 'Fertiliaaedi Vnd Graced 

 Intensively, (J. G. Archibald). The department has cooperated during 

 the past two years in a study of an intensive system of grassland man- 

 agement being carried out on the College farm. A study has been made 

 of the chemical composition of grass as affected by the intensive fertilizer 

 treatment and grazing which the system involves. Results for 1928 have 

 been published in the Journal of the American Society of Agronomy for 

 June 1929. The study for 1929 has not yet been completed. Briefly: the fer- 

 tilizer treatment increased the percentage of nitrogen, phosphorus, and 

 ether extract, and decreased slightly the percenta,ge of crude fibre and 

 calcium, in the dry matter of the grass. Acre production of all consti- 

 tuents was increased, nitrogen being nearly dou'bled^ while phosphorus 

 and ether extract were increased by about one-half. 



A stuiiy of the seasonal variations in composition showed that grass 

 kept in the vegetative stage by grazing may be quite different in chemical 

 composition in midsummer from what it was in the spring. The seasonal 

 factors, rainfall, temperature and sunshine, exert their influence irrespec- 

 tive of the stage of growth of the plant. 



Utilization of Onions by Canning. (C. P. Jones). The object of the 

 studies on the chemistrj- of the onion has been ta ascertain (1) its min^ 

 eral and proximate food constituents, (2) the cause of its discoloring ac- 

 tion upon the tin in which it is processedi, and (3) the reason for the 

 darkening of the onion itself in the canning process. Manj'^ of the in- 

 organic and organic constituents of the onion have been already deter- 

 mined. Furtlier additions relative to both are to be made. 



Discoloration of Can. Preliminary studies made on the discoloration 

 of plain tin cans by commercially processed fruits, vegetaibles', flesh pro- 

 ducts and soups, and by laboratory canned materials indicated that sulfur 

 from the protein molecule caused the discoloration. Experiments conduct- 

 ed with cysteine hydrochloride further confirmed this view. In the case 

 of the onion, other sulfur compounds are present in addition to those 

 associated with the protein molecule, and Mere therefore considered as 

 possible discoloring factors. 



Unfortunately, lack of laboratory facilities prevented the extraction, 

 recovery and consequent identification of the sulfur oils contained in the 

 onion. However, several analogous oils (technical alkj'l sulfide and disul- 

 fide, allyl sulfide, and mustard oil) were investigated as to the probability 

 of such sulfur compounds constituting discol'bring agents. This was found 

 not to be the case, with the exception of mustard oil. The presence of 



