February 1: 2 p. m., condition good, walked about, appetite good, passed 155 cc dark, reddish-brown urine since 5.30 p. m. previous day. _Rabbit 279. Gray and white female. Weight, 1,320 grams._ February 24: 10.09 a. m., 6 cc 2 per cent caffein passed rapidly into jugular vein; 10.15 a. m., involuntary twitching of muscles of legs, but no other symptoms; 10.23 to 10.26, 3 cc of 2 per cent caffein injected; 10.27 to 10.28, 2 cc 2 per cent caffein injected, convulsions; 10.29, convulsions stopped; 10.32, convulsions; 11 a. m., rabbit lying on its side, anterior extremities paralyzed, posterior extremities contracted, no clonic convulsions, breathed deeper and more slowly than normal; 11.10 a. m., rabbit died, had no convulsions immediately before death; amount of caffein injected, 11 cc 2 per cent solution, or 0.166 gram per kilo. _Rabbit 254. Belgian hare, female. Weight, 1,285 grams. Diet, oats._ November 12: 1.30-1/3 to 1.47¾ p. m., received 10.8 cc 2 per cent caffein from burette into ear vein, after injection of 6.2 cc dyspnoea, 6.7 cc struggling, convulsions; at 1.50½ p. m., released from holder, paralysis especially marked in the anterior extremities; 1.50 p. m., recovered, survived; total amount injected, 10.8 cc 2 per cent caffein in 17 minutes and 25 seconds, or 0.16 gram caffein per kilo. _Rabbit 255. Belgian hare, male. Weight, 1,105 grams. Diet, oats._ November 12: 2.31¾ to 2.35¼ p. m., received 3.7 cc; from 2.37-1/6 to 2.46-1/6 p. m., 5 cc injected; after injection of 6.1 cc convulsions followed by dyspnoea, then continuous struggling; when 8.3 cc were injected rabbit had another convulsion; 2.47 p. m., tonic contraction of anterior extremities; amount injected, 8.7 cc (158 mg per kilo) in 15 minutes and 35 seconds. _Rabbit 567. Gray female. Diet, oats._ February 6: Injection began at 4.11 p. m.; 4.18, convulsions after injection of 5 cc 2 per cent caffein; 4.21, convulsion after total injection of 8 cc; 4.24 p. m., injection resumed and 2 cc more introduced; 4.28 p. m., convulsions, injected 2 cc more; total caffein injected, 12 cc, or 162 mg per kilo; 4.40 p. m., rabbit paralyzed in posterior extremities; 5 p. m., found dead.