350 mg per kilo is not the minimum fatal dose for the normal rabbit. Indeed, the experiment on rabbit 239 lends support to this view, thus furnishing additional evidence of difference in the resistance to caffein in the two varieties of rabbits. TABLE 2.--_Administration of caffein by mouth._ SERIES A. ------+--------+-------+-----------+--------------+-------+----------- Rabbit| |Caffein| | Duration | | No. | Weight.| per | Symptoms | of life. | Diet. |Remarks. | | kilo. | | | | ------+--------+-------+-----------+--------------+-------+----------- |_Grams._| _Mg._ | | | | 248 | 1,170 | 330 |3 hours |Survived |Oats |Gray. | | | 10 minutes| | | 241 | 1,380 | 290 |2 hours | do. | do. |White male. | | | 15 minutes| | | 249 | 890 | 325 |3 hours | do. | do. |Gray male. ------+--------+-------+-----------+--------------+-------+----------- SERIES B. ------+--------+-------+-----------+--------------+-------+----------- 239 | 935 | 363 | |Survived |Oats |Gray male. 254 | 975 | 369 | |About 2 days | do. |Gray female. 267 | 1,050 | 342 |50 minutes |1 hour | do. |White. | | | | 4 minutes | | 268 | 1,100 | 363 | |About 3 hours | do. | Do. 419 | 1,600 | 350 |6 hours |Less than | do. |Gray male. | | | | 24 hours | | 420 | 1,250 | 352 |1 hour |2 hours | do. | Do. | | | | 35 minutes | | 421 | 1,485 | 351 |6 hours |Less than | do. | Do. | | | | 24 hours | | 424 | 1,295 | 293 |2 hours |22 hours | do. | White male. 423 | 1,205 | 300 | do. |Less than | do. | Do. | | | | 19 hours | | 422 | 1,440 | 291 | do. |2½ hours | do. | Do. ------+--------+-------+-----------+--------------+-------+------------ INJECTION INTO THE PERITONEAL CAVITY. In a number of experiments caffein was introduced into the peritoneal cavity. Rabbits of different varieties receiving a diet of oats or carrots were employed for this purpose; food and water were given ad libitum. The minimum doses required to induce symptoms or cause death in these animals were determined; tests with caffein were also made on young rabbits in order to study the influence of age on the resistance to this substance. The results are shown in the following experiments: SERIES A. In this series large doses were administered, approximating 0.3 gram per kilo. _Rabbit 71. Gray female. Weight, 1,659 grams._