Using a synthetic milk diet, calves receiving 1.2% DL-methionine exhibited no demonstrable choline requirement, as measured by growth and liver ether extract. On a diet supplying 0.8% methionine, fatty livers developed in the absence of choline. A study was made of the ability of calf liver homogenates to methylate homocysteine to form methionine, when betaine served as methyl donor; to methylate guanido-acetic acid, when meonine served as the methyl donor, and to oxidize choline. It was found that while calf liver homogenates would carry out all of these reactions, the activity of the calf liver enzymes was very much less than that of rat liver homogenates.