VITAMIN C 209 



dried grains and hays, supplemented in one case by a silage made from 

 corn that had well matured and partly dried but had not been frozen, 

 and in another case by a small amount of silage and a considerable 

 amount of hybrid sugar mangels. Each variety of milk was tested by 

 feeding it to guinea pigs as a supplement to a basal scurvy-producing 

 ration of heated ground alfalfa hay, rolled oats and common salt. The 

 amounts fed varied from 15 to 50 cubic centimeters daily of the summer 

 pasture milk and from 15 to 100 cubic centimeters of the dry feed milks. 

 Full protection was secured by the daily consumption of 50 cubic centi- 

 meters of the summer pasture milk and 75 cubic centimeters of the 

 dry-feed milk. 



Butcher, Eckles, Dahle, Mead and Schaefer (1920) determined in 

 a similar manner the vitamin C content of the mixed milk of two cows, 

 first on dry feed and later smaller amounts of the dry feed supple- 

 mented by pasture feeding. Greater protection against scurvy was 

 secured with 20 cubic centimeters of the summer milk than with 60 

 cubic centimeters of the winter milk as thus produced. The response 

 to pasture feeding was very rapid, being noticeable within two weeks 

 after the cows were put to pasture. Hess, Unger and Supplee (1920) 

 also showed that the milk of cows on pasture is much richer in vitamin 

 C than dry fodder milk and that the antiscorbutic vitamin in the feed 

 is rapidly secreted into the milk rather than stored in the body. 



That winter-produced milk under certain conditions may be as rich 

 as summer-produced has been demonstrated by Kierferle and Zeiler 

 (1926) and by MacLeod (1927). The former compared the antiscor- 

 butic properties of milk produced by cows on three different rations, 

 one consisting largely of silage prepared from young second crop grass 

 of good quality, another of hay and another of brewers' grains. On 

 a basal diet of oats and autoclaved powdered alfalfa with one per cent 

 of common salt, guinea pigs were completely protected from scurvy 

 by 45 cubic centimeters daily of the silage milk and by 60 cubic centi- 

 meters of the dry feed milk, while 60 cubic centimeters of the milk 

 from cows fed brewers' grains did not afford complete protection. 



MacLeod (1927) determined the vitamin C content of milk from 

 cows receiving a ration of mixed grains, alfalfa hay, corn silage, and 

 beet pulp. The cows were allowed exercise in a yard but had no access 

 to pasture throughout the year. Of the milk thus produced 30 cubic 

 centimeters fed 6 days a week in two or three feedings a day afforded 

 considerable protection since none of the guinea pigs receiving this 

 amount died before the end of 90 days. For complete protection 50 

 cubic centimeters was found sufficient. The experiment was continued 



