The object of these experiments was to determine the minimum lethal
dose; 0.2 to 0.15 gram of caffein per kilo was injected into the
rabbits of this series.
_Rabbit 69. White female. Weight, 1,714 grams._
January 20: 10.15 a. m., 6 cc 2 per cent caffein, aqueous solution,
injected into peritoneal cavity. No symptoms, under observation for 45
minutes, rabbit defecated rather copiously; feces were soft; 11 a. m.,
6 cc 2 per cent caffein, aqueous solution, injected into peritoneal
cavity, no symptoms, under observation for 40 minutes; 11.40, 6 cc 2
per cent caffein injected into peritoneal cavity; 11.45, rabbit is
restless, reflexes increased.
_Rabbit 70. Gray and white female. Weight, 1,487 grams._
January 20: 1.30 p. m., 15 cc 2 per cent aqueous solution of caffein
(0.2 gram per kilo) injected into the peritoneal cavity; 2.20 p. m., no
symptoms.
January 30: About 2 p. m. rabbit died.
February 1: _Autopsy_: Cirrhosis of the liver; enteritis of small
intestines; stomach and kidneys normal.
_Rabbit 93. Maltese, male. Weight, 1,197 grams._
March 2: 11.30 a. m., 12 cc of 2 per cent caffein (200 mg per kilo)
injected into peritoneal cavity; 11.35 a. m., while being released from
holder, tetanus occurred, repeated attacks later, clonic convulsions
with tonic rigidity of posterior extremities during the attacks as
well as during intervals, anterior extremities were relaxed during the
intervals between the attacks, opisthotonos of cervical region but
kyphosis in lumbar region were observed, no salivation nor dilatation
of the pupils; 2 p. m., rabbit died.
_Rabbit 92. Yellow female. Weight, 1,388 grams._
February 25, 4.15 p. m., 14 cc 2 per cent caffein (0.2 gram per kilo)
injected into peritoneal cavity; 4.20 p. m., restlessness and increased
reflexes, rabbit found stretched out in cage, but raised himself on his
legs again; 4.45, general tremor when touched.
February 26: 9 a. m., rabbit found dead. _Autopsy_: Hemorrhage into
abdominal muscles at site of injection; hemorrhage also in walls of
stomach opposite similar spot in abdominal wall.
_Rabbit 309. Belgian hare, female. Weight, 1,500 grams. Diet, oats._
March 2: 2.05 p. m., 2 per cent caffein solution (0.2 gram per kilo)
injected into peritoneal cavity; 2.25 p. m., found dead, no urine found
in bladder.
_Rabbit 307. Belgian hare, female. Weight, 1,320 grams. Diet, oats._
March 2: 12 noon, urine obtained from bladder, clear amber colored, no
albumin, no reduction; 12.06 p. m., 10 cc of 2 per cent caffein (0.151
gram per kilo) injected into peritoneal cavity; 1.30 p. m., rabbit
placed on floor, runs around but anterior and posterior extremities
soon extended, in tonic condition; 2.25 p. m., reflexes increased,
paralysis of extremities, dyspnoea; 4.50 p. m., about 100 cc urine
collected, no albumin, reduction of Fehling's solution moderate.
March 3: 9.30 a. m., posterior extremities extended and rigid,
anterior extremities paralyzed, respiration less frequent and deeper
than normal. Rabbit died at 11.50 a. m.; urine collected since 4.50
p. m. previous day gave very heavy reduction of Fehling's solution.
_Autopsy_: Animal in good condition; in the left axillary region was
observed a hemorrhage into the subcutaneous and muscular tissue of
that region. The ventral portion of the large colon, in contact with
the ventral abdominal wall, showed a hemorrhagic area about one-half
inch in length, such as might be produced by a puncture or bruise of
the colon through the abdominal wall. A small portion of the small
intestine adjacent to the colon was affected in a similar manner. All
internal organs were apparently normal.
_Rabbit 308. Belgian hare, female. Weight, 1,350 grams. Diet, oats._
March 2: 11.45 a. m., urine obtained from bladder, no albumen, no
reduction; 11.50 a. m., 10 cc 2 per cent caffein (0.15 gram per kilo)
injected into peritoneal cavity; 1.30 p. m., not very active, no
abnormal symptoms otherwise; 3.30 p. m., rabbit looked depressed, made
very little attempt to move about, remained in one position most of
the time when placed on floor; 4.30 p. m., 180 cc urine collected, no
albumen, reduction of Fehling's solution moderate.
March 3: 9.30 a. m., rabbit looks normal, is able to walk but is easily
fatigued when made to walk about or when placed on his side, followed
by paralysis of anterior extremities, posterior extremities apparently
normal, about 90 cc of urine collected at noon was free from albumen,
did not reduce Fehling's solution.
March 4: 11 a. m., lying on his side in cage, anterior extremities
limp, posterior extremities extended and rigid, is in dying condition.
March 5: 9 a. m., found dead. _Autopsy_: Liver engorged; spleen
congested, but not enlarged; kidneys, some congestion in cortex;
stomach filled, mucosa thickened and easily pulled off; petechial
hemorrhages on serosa of colon.