Experiments with 2 decigrams per kilo constituted this series.
_Guinea pig 20. Female. Weight, 497 grams. Diet, oats._
April 2: 5 cc 2 per cent caffein injected subcutaneously at 11.30 a. m.;
1.50 p. m., spasm of short duration. Died at 3 p. m., three and
one-half hours after injection.
_Guinea pig 38. Brown male. Weight, 570 grams. Diet, carrots and oats
week previous to injection._
February 11: 3.50 p. m., 6 cc 2 per cent caffein injected
subcutaneously in back (210 mg per kilo); 4.15, reflexes increased, had
convulsion of short duration when disturbed; 4.45 p. m., on handling,
repeated convulsion and paralysis; 5 p. m., guinea pig lying on his
side, respiration difficult and labored.
February 11: 5.05 p. m., guinea pig found dead, 2 hours and 15 minutes
after injection.
_Guinea pig 37. Male. Weight, 820 grams. Diet, carrots and oats during
week preceding the injection of caffein._
February 11: 3.35 p. m., 8.5 cc 2 per cent caffein injected
subcutaneously in the back; 5 p. m., pig very sensitive, anterior
extremities paralyzed when handled, frequent spasms of posterior
extremities, no symptoms noticed before 5 p. m., although watched all
the time; 5.05 p. m., guinea pig on his legs and looked normal. No
attack on handling.
February 12: 9 a. m., found dead; died within 18 hours.
_Guinea pig 13. Female. Weight, 618 grams. Diet, oats._
March 29: 2.45, 6 cc 2 per cent caffein injected subcutaneously (0.194
grams per kilo).
March 30: Died at 4 p. m., 25 hours after injection.
_Guinea pig 36. Male. Weight, 850 grams. Fed oats and carrots for one
week previous to injection._
February 11: 3.30 p. m., 8.5 cc 2 per cent caffein injected
subcutaneously into back; 5 p. m., somewhat more sensitive than normal,
no other symptoms, no effect on handling; 5.05 p. m., no symptoms.
February 12: 9 a. m., found dead, about 18 hours after injection.
The results of these experiments, as observed in five guinea pigs,
indicate that two decigrams of caffein per kilo of animal produce
symptoms within a half to about two and a quarter hours after
injection. Death followed in two guinea pigs 70 minutes to 1 hour
after the first manifestations of symptoms. Two others died during the
night, while one lived 25 hours after the injection of caffein. Even
2 decigrams caffein per kilo weight might therefore be fatal to the
guinea pig. Experiments carried out later have shown, however, that the
resistance to caffein is appreciably greater in some guinea pigs. This
is indicated by the following experiments, in which doses of 0.2 to
0.24 gram caffein per kilo were administered by the same path.