48 THE TOXICITY OF CAFFEIN. 





 Guinea pig 53. Brown and white male. Weight, 490 grams. 



October 1: 9.45 a. m., 4 cc, 2 per cent caffein (163 mg per kilo), injected into peri- 

 toneal cavity; 4.30 p. m., no symptoms developed since injection. 



October 3: 2 p. m., alive. 



October 8: Found dead. Autopsy: Congestion of lungs, spleen, liver, kidneys, and 

 small intestines. 



SERIES C. 



Guinea pig 59. Gray and white. Weight, 375 grams. Diet, oats. 



October 3: 2 p. m., 3.75 cc(0.2 grain per kilo) injected into peritoneal cavity; 2.15 

 p. m., reflexes increased but not markedly; 4 p. m., reflexes still more increased; 

 no other symptoms; 5.30 p. m., no symptoms. 



October 4: 8.50 a. m., guinea pig alive and active. 

 Guinea pig 58. Brown and white. Weight, 880 grams. Diet, oats. 



October 3: 2 p. m., 3.8 cc caffein (0.2 gram per kilo), 2 per cent solution, injected 

 into peritoneal cavity; 2.10 p. m., hind lees extended, then tetanus; attack lasted a 

 few seconds, after which pig raised himself on his legs, but reflexes remained much 

 exaggerated; 4 p. m. to 5.30 p. m., no symptoms of caffein intoxication. 



October 4: 8.50 a. m., guinea pig alive and active. 

 Guinea pig 56. Gray and white male. Weight, 440 grams. Diet, oats. 



October 1: 11.30 a. m., received 4.6 cc of 2 per cent caffein solution (0.2 gram per 

 kilo) into abdominal cavity; 11.45 a. m., stiffness and rigidity of posterior extremi- 

 ties, reflexes increased; 12.30 p. m., hind legs paralyzed, reflexes increased; 4.35 

 p. m., no symptoms, guinea pig in good condition. 



October 3: Still alive, in good condition. 



October 14: Died. Autopsy: Anterior lobe of right lung hepatized. Small portion 

 of small intestine edematous. Other organs normal. 

 Guinea pig 55. White and yellow male. Weight, 690 grams. Diet, oats. 



October 1: 11.30 a. m., received 6.5 cc of 2 per cent solution caffein (188 mg per 

 kilo) into peritoneal cavity; 11.40 a. m stiffness in all extremities, reflexes markedly 

 increased; 12.30 p. m., reflexes increased, anterior and posterior extremities paralyzed ; 

 3 p. m., found dead. 



SERIES D. 



Guinea pig 67. Gray and yellow male. Weight, 330 grams. Diet, oats. 



October 5: 11.25 a. m., 4 cc of 2 per cent caffein injected into peritoneal cavity 

 (240 mg per kilo); 11.30 a. m., tetanus survived, convulsipns off and on. Death 

 at 2.55 p. m. Autopsy: Severe gastroenteritis; kidney petechiated; congestion of 

 lungs and liver. 

 Guinea pig 63. Gray and white male. Weight, 340 grams. Diet, oats. 



October 5: 11.20 a. m., 4 cc of 2 per cent caffein (235 mg per kilo) injected into 

 peritoneal cavity. 



October 14: Alive and in good condition. 

 Guinea pig 64. Brown and black female. Weight, 305 grams. 



October 5: 11.35 a. m., 3.8 cc 2 per cent solution caffein (250 mg per kilo) injected 

 into peritoneal cavity; 11.40 a. m., tetanus survived, convulsions off and on, died 

 at 4.15 p. m. Autopsy: Findings exactly the same as in No. 67. 



Examination of the results of the experiments by intraperitoneal injections showed 

 that 0.2 gram caffein per kilo was toxic in two guinea pigs (Nos. 59 and 58). Severe 

 symptoms were observed within 15 minutes in No. 56 and within one hour in No. 

 55 after the administration of approximately the same dose of caffein. One of these 

 died within three and one-half hours; the other, No. 56, made a good recovery from 

 the acute effects. This amount of caffein may be regarded, therefore, as the mini, 

 mum toxic dose for the guinea pig when injected into the peritoneal cavity. This 

 is corroborated by the experiments of series B in which smaller doses failed to show 

 any muscular, nervous, or respiratory symptoms, nor were there any after effects 

 noticed, as all of them survived and were kept under observation for some time. 

 The guinea pigs of series A, however, seem to contradict these results. It will be 

 remarked that appreciably smaller doses induced symptoms in all of them, and one 

 case terminated fatally. The seasonal variation, as already pointed out, is in all 

 probability likewise responsible for the difference in the resistance between the 



