------+--------+-------+----------+----------+-------+-------+-------- Number| |Caffein|Appearance| Duration | | | of pig|Weight. | per | of | of | Diet. | Month.|Remarks. | | kilo. | symptoms.| life | | | ------+--------+-------+----------+----------+-------+-------+-------- |_Grams._|_Gram._| | | | | 129 | 855 | 0.280 |40 minutes|Less than |Hay and|June |Male. | | | | 8 hours| oats | | 130 | 800 | .300 |30 minutes|Less than | do. | do. | Do. | | | | 18 hours| | | 131 | 860 | .280 |20 minutes| do. | do. | do. | Do. 135 | 955 | .150 |1 hour 50 |6 days | do. | do. | Do. | | | minutes | | | | 134 | 740 | .160 |3 hours |4 days | do. | do. | Do. (1)137| 925 | .150 |50 minutes|6 days | do. | do. | Do. (1)136| 1,000 | .150 | do. |Survived | do. | do. | Do. 126| 980 | .200 |20 minutes|27 hours | do. | do. | Do. 127| 760 | .200 |1 hour |28 hours | do. | do. | Do. 128| 1,075 | .200 |3 hours |7 hours | do. | do. | Do. ------+--------+-------+----------+----------+--------+------+-------- (1) Subcutaneous injection for comparison. SUMMARY. A survey of the results obtained in experiments on guinea pigs shows that the mode of introduction of caffein exerts but little influence on its toxicity. On careful analysis it will be observed that the rate of absorption after the administration of caffein by mouth, subcutaneously, or intraperitoneally is about the same for the time of appearance of symptoms. The persistence of the symptoms of caffein intoxication observed in these experiments for 24 hours after administration points to slow elimination, which may be expected, owing to the fact that the guinea pigs passed but little urine and caffein is not diuretic for these animals. The prolonged presence of caffein in the body probably exerts a harmful influence or after effect, which may account for the delayed death of some animals many days after a single dose of caffein was given. Among the factors which undoubtedly influence toxicity, season should be considered, while the presence of a diseased condition undoubtedly tends to decrease the resistance of the guinea pig to caffein. Diet was without any influence on the toxicity of the single dose of caffein. EXPERIMENTS ON CATS.