FiTC'HETT. — Physiological Action of Tutin. 



309 



(b.) Comparison of Action of Tutin and Picrotoxin. 



SoUmann's statement that 0-001 per cent, picrotoxin causes death in 

 four to nine hours was tested by the improved method (see Table V, No. 85). 

 Three fish were put into 1,000 c.c. of 0-001 picrotoxin at 11 a.m. Up to 

 8.30 p.m. no symptoms were seen, though the fish were under observation 

 all day. At 8.30 they began to swim more frequently near the surface, 

 and when seen next day one was dead, but the others were unaffected, and 

 were returned to the trough at the end of twenty-four hours. A 0-001 per 

 cent, of tutin (Exp. 83) showed almost similar results. Previous to this 

 an experiment where 0.00075 per cent, and 0-0005 per cent, picrotoxin 

 and the same strengths of tutin were tested gave doubtful results, because 

 the amount of fluid was too small (Table V, Nos. 81, 82, 78, 79). 



In other experiments picrotoxin was compared with tutin in a strength 

 of 0-004 per cent. All the picrotoxin fish died — two at twelve hours and 

 one at 294 hours (Exp. 100) ; while of the tutin fish two died — at twelve 

 hours and at eight hours and a half — and one recovered (Exp. 95). With 

 a 0-005-per-cent. solution of picrotoxin all three fish died — viz., at 3| hours, 

 at llf hours, and at 12f hours (Exp. 107) ; while tutin of the same strength 

 caused death to all at 22|^ hours and at twenty-three hours (Exp. 106) : so 

 it would appear that picrotoxin is more lethal than tutin in equal per- 

 centages. 



