It has been previously shown that the administration of alloxan leads to the destruction of the islets of Langerhans in the pancreas (Dunn, Sheehan & McLetchie, 1943) with a subsequent development of a true diabetic condition which results in a simultaneous increase of both blood sugar and ketone body levels. A small number of workers have previously studied this condition in ruminants. Jarrett (1946) administered alloxan intravenously to sheep in doses varying from 90 to 200 mg per Kg body weight. Only blood sugar values were determined and these rose to levels of 230, 250 and 310 mg per cent in three of the animals which survived for a long period (14, 47 and 53 days respectively). McCandless, Woodward & Dye (1948) also administered alloxan to sheep in doses varying from 75 to 125 mg per Kg. The blood sugar and ketone body values, obtained sporadically during a ten day period, ranged from 146 to 218 mg per cent for the former and 11 to 51 mg per cent for the latter. Survival times varied, ranging from only 85 hours to 157 days. Schultz & Smith (1951) dosed one goat with 90 mg of alloxan per Kg. As a result the ketone body and blood sugar levels rose to 60 and 200 mg per cent respectively and the animal survived for 14 days. Finally Goetsch (1957) administered 100 mg of alloxan per Kg to non-pregnant ewes. In this instance blood sugar and ketone body levels were determined only at 24 and 48 hours after the dosing of the drug. During this period the former were found to rise on an average to a maximum of 260 mg per cent and the latter to one of 4 • 9 mg per cent. In the present experiment the animals were dosed with approximately 50 mg of alloxan per Kg and both blood sugar and ketone body levels determined. In addition the latter were partitioned into their individual fractions.