36 



THE TOXICITY OF CAFFEIN. 



mg of caffein per kilo injected into the lumbar muscles produced mild symptoms only. 

 Experiments with larger doses showed that 0.180 gram caffein per kilo may cause 

 death. It will be noticed, on the other hand, that rabbit No. 455 survived a dose of 

 0.2 gram per kilo. New experiments were therefore carried out in which the same 

 amounts of caffein in proportion to the weight of the animals were injected into the 

 lumbar muscles as into the gluteal muscles. As shown in the experiments of series D, 

 one rabbit (No. 581) died shortly after caffein was injected into the lumbar muscles; 

 two recovered. Two of the three which received injections into the gluteal muscles 

 were found dead the next day; one recovered. Post-mortem examination failed to 

 indicate the presence of any abnormalities. The rate of absorption of caffein from 

 the gluteal and from the lumbar muscles seems to be, therefore, the same, or not to 

 differ very much. The observations of Auer and Meltzer 7 are of interest in this con- 

 nection. According to their investigations adrenalin is more rapidly absorbed from 

 the lumbar than from the gluteal muscles. This is in all probability due to the greater 

 delicacy of the test they employed (since they judged the rate of absorption by the 

 effect of adrenalin on blood pressure) as well as to the much greater activity of the 

 substance. 



TABLE 4. Intramuscular injections. 



SERIES A. 



SERIES B. 



SERIES C. 



SERIES D. 



Examination of Table 4 shows that 14 rabbits received from 180 to 210 mg caffein 

 per kilo. The appearance of symptoms in these rabbits varied considerably. In 

 some increased reflexes could be noticed in 10 to 15 minutes after the injection of 

 caffein; in others it was delayed 2 or 3 hours. It might be added that the onset of 

 symptoms occurred in many cases very soon after the administration of the drug 

 on an average about 10 to 30 minutes after the drug was injected. After smaller 



