Complete data is given of a digestion trial made with two Holstein cows, one being feed maintenance ration plus protein, the other maintenance ration plus carbohydrate. The digestive co-efficient of both cows were about normal. The cow which received the maintenance ration plus B. Albumen digested 67.87% of whole ration and the one which received maintenance ration plus carbohydrate digested 66.10% of whole ration. Both of which is a little lower than the theoretical. The following authorities have been consulted: Echol’s Missouri Station Bulletin Research 2 and 5. Henry’s, Shermans, Armsby’s, and Farmers Bulletin 346. Bulletin 22 Revised Department of Agriculture. / Master of Science