ACUTE INTOXICATION GUINEA PIGS. 49 



guinea pigs of series A and B. Tests were made also to determine the minimum 

 fatal dose. For this purpose the experiments of series D were performed. The 

 resistance of No. 63 in this series is quite striking. We are unable to explain such 

 a discrepancy in the results obtained under practically uniform conditions. The 

 minimum fatal dose of caffein, when injected into the peritoneal cavity, is therefore 

 about 240 to 250 milligrams per kilo. These amounts, it will be observed, were 

 rapidly fatal, in striking contrast to the results obtained when such doses were injected 

 subcutaneously. This is probably due to a better absorption from the peritoneal 

 cavity than from the subcutaneous tissues. 



ADMINISTRATION BY MOUTH. 



All the guinea pigs in these experiments were kept on a diet of hay and oats and 

 were of large size. The tests were made with different doses of caffein in order to 

 determine the limits of toxicity when the drug was administered by mouth. 

 Guinea pig 129. White and black male. Weight, 855 grams. Diet, oats and hay. 



June 6: 2.20 p. m., 12 cc of 2 per cent caffein (0.28 gram per kilo) by mouth; 3 

 p. m., reflexes increased; 5 p. m., reflexes still more increased; no other symptoms. 



June 7: 9 a. m., found dead; guinea pig passed 75 cc urine, which was almost color- 

 less. Autopsy: Heart and blood vessels injected; lungs congested; small intestines 

 congested; other organs apparently normal. 

 Guinea pig ISO. Black and brown male. Weight, 800 grams. Diet, oats and hay. 



June 6: 2.30 p. m., 12 cc of 2 per ce*nt caffein (0.3 gram per kilo) administered by 

 mouth; 3 p. m., reflexes increased; 5 p. m., increase of reflexes greater than at 3 

 p. m. 



June 7: 9 a. m., found dead; only a few cubic centimeters of urine passed since 

 4 p. m. Autopsy: Heart and blood vessels injected; lungs congested; small intes- 

 tines congested slightly. 

 Guinea pig 181. White and yellow male. Weight, 860 grams. Diet, oats and hay. 



June 6: 2.40 p. m., 12 cc 2 per cent caffein administered by mouth; 3 p. m., reflexes 

 increased; 5 p. m., reflexes still more marked. 



June 7: 9 a. m., found dead, pig passed about 5 cc urine since 4 p. m. of previous day. 

 Autopsy: Same as in No. 130. 

 Guinea pig 136. White and black male. Weight, 1,000 grams. Diet, oats and hay. 



June 9: 4 p. m., 7.5 cc 2 per cent caffein solution injected subcutaneously into the 

 back; 4.50 p. m., reflexes increased. 



June 10: 9.30 a. m., more sensitive than normal guinea pigs, but reflexes not quite so 

 marked as at 5 p. m. previous day, about 15 cc urine passed since caffein was injected, 

 reduction of Fehling s solution considerable, no albumin. 



June 13: Alive and in good condition. Appetite good. (NOTE. Parallel test with 

 urine from two guinea pigs which did not receive caffein failed to show reduction of 

 Fehling's solution.) 

 Guinea pig 137. White and brown male. Weight, 925 grams. Diet, oats and hay. 



June 9: 4 p. m., 7 cc 2 per cent solution caffein injected subcutaneously; 4.50 p. m., 

 reflexes increased. 



June 10: Reflexes less marked than at 5 p. m. previous day, but is more sensitive 

 than normal guinea pig, about 10 cc urine passed since injection of caffein, moderate 

 amount of reduction of Fehling's solution. 



June 13: Guinea pig alive, appetite good, condition good. 



June 16: 9 a. m., found dead. 

 Guinea pig 135. White and black male. Weight, 955 grams. Diet, hay and oats. 



June 9: 3 p. m., 7.5 cc 2 per cent caffein solution given by mouth through stomach 

 tube; 4.50 p. m., reflexes increased. 



June 10-: Ileflexes less than on previous day and less marked than in No. 136, a few 

 cubic centimeters dirty brown urine collected but could not be tested for reduction. 



June 13: Condition good, appetite good. 



June 16: 9 a. m., found deacf. 

 Guinea pig 134- White and brown male. Weight, 740 grams. Diet, hay and oats. 



June 9: 2.55 p. m., 6 cc warm 2 per cent caffein solution given by mouth through 

 stomach tube; 4.50 p. m., reflexes increased. 



18594 Bull. 14812 4 



