FiTCHETT. — Physioloyical Action of Tutin. 301 



357 grams (Exp. 18). No symptoms followed beyond those that generally 

 appeared in the first experiment after a non-lethal dose had been adminis- 

 tered. One hour and three-quarters later the bird was apparently normal, 

 and on the day following the experiment was quite well. Here a dose of 

 15 mlgm. per kilo was without efTect. It was noted that the crop in this 

 bird was full, but, though this was recognised as probably influencing the 

 result in some degree, the fact that the first bird was unaffected by a dose 

 of 16 mlgm. per kilo was so striking that it was thought likely that 15 mlgm. 

 per kilo was below the lethal minimum. It was therefore decided to give 

 a dose equivalent to 16 mlgm. per kilo to another pigeon (Exp. 19). In 

 administering the poison to this bird, by an accident a few drops of the 

 solution were lost, and the deficiency was made good by an allowance of 

 5 extra minims (Exp. 15). In three minutes the bird was in convulsions, 

 and in nine minutes was dead. As no satisfactory conclusion could be 

 drawn from this experiment it was repeated (Exp. 20), but the subject became 

 convulsed within a minute and a half, and died five minutes after the 

 administration. 



It was then decided to repeat the dose of 15 mlgm. per kilo, using the 

 bird that had previously withstood this dose, but taking care that its crop 

 should be empty (Exp. 21). At 5.14 the dose was given. No symptoms 

 appeared till seven minutes had elapsed, when it began to retch. In twenty 

 minutes convulsions appeared, and in thirty-five minutes it was dead. It 

 was noted that the onset of symptoms was slower and the time to kill longer 

 in this case than in the case where 16 mlgm. per kilo were given (thirty-five 

 minutes as against five minutes). It was therefore thought worth while 

 to repeat the dose of 15 mlgm. per kilo, using a bird that had not been 

 starved. This was done (Exp. 22), with the result that the bird died in 

 twelve minutes. 



It being now clear that the minimum lethal dose was much exceeded, 

 two pigeons were taken (Exps. 5, 23, 24), and to one was given a dose equiva- 

 lent to 13 mlgm. per kilo, to the other 12 mlgm. per kilo. In the case of 

 the bird with the larger dose, death resulted in nineteen minutes ; but the 

 bird that had received 12 mlgm. per kilo showed a very gradual onset of 

 symptoms, and did not die till two hours and sixteen minutes after the 

 administration. This bird was a young one (still squeaking), though it 

 weighed 363 grams. It was thought that the age in this case may have 

 influenced the result, so a dose of 12 mlgm. per kilo was given to an adult 

 bird. Death occurred, however, in forty-six minutes — a hundred minutes 

 earlier than in the case of the young bird (Exp. 25). 



A drop in dosage was now made to 9 mlgm. per kilo, and the bird that 

 received this dose was not affected (Exp. 26). The same result was noted 

 in a bird receiving 9'5 mlgm. per kilo (Exp. 27) ; but the next bird, which 

 received a dose of 10 mlgm. per kilo, died in forty-five minutes (Exp. 28). 

 This was a young bird (squeaking), weighing 330 grams. The same dose 

 (10 mlgm. per kilo) was therefore given to an adult bird (Exp. 29), which 

 recovered after exhibiting symptoms such as vomiting and slight convulsive 

 movements of the wings. 



Of the four birds that had received 10 mlgm. per kilo, one only (a young 

 bird) had died. A dose of 10*25 mlgm. per kilo was therefore given to an 

 adult bird, with the result that it died in seventy-five minutes (Exp. 30). 



The results of these experiments are tabulated on the following page 

 (Table 1). 



