446 Transactions of the Canadian Institute. [Vol. VII. 



Daphnia and the larva of an aquatic insect lived three days. 



One hydra immersed at 10.40 a.m. was dead at 5 p.m. Its body 

 was partly disintegrated and many paramoecia appeared to be feeding 

 on it. Another hydra on being placed in the extract contracted its 

 tentacles, detached itself from its support, contracted the lower half of 

 its body, voided the intestinal contents, and appeared to be dead in two 

 hours. It revived in fresh water. 



A colony of vorticellas at first showed no signs of discomfort ; the 

 cilia kept on moving, and the stalks contracting spirally. Soon the 

 stalks ceased their movements ; a little later the cilia stopped ; the 

 animals took the spherical form and within one and a half hours all were 

 apparently dead. 



A rock bass weighing seventy grams when placed in 1,300 c.c. of the 

 extract became moribund in twelve minutes. All of the fish revived in 

 from five to twenty minutes when returned to fresh water. 



A perch weighing thirty grams when placed in a jar containing 400 

 c.c. of the pine water with air bubbling rapidly through it was moribund 

 in ten minutes. 



June 1 6th. Up to this time my experiments with this extract had been 

 made with strong solutions. To-day a series of experiments were begun 

 for the purpose of ascertaining, if possible, how long the same sawdust 

 would continue to give off poisonous solutions when the saturated water 

 was drained off and fresh water added from time to time. 



With this end in view 360 grams of white pine sawdust were placed 

 in a cheese cloth bag at 9 a.m. and sunk to the bottom of a small glass 

 aquarium, 12 in. x 8 in. x 6 in., containing 7,000 c.c. of tap water. Two 

 hours after, 800 c.c. were siphoned off from the extract at the bottom of 

 the vessel. This was found to be very slightly poisonous to adult fish. 

 Next morning at 10 a.m. 800 c.c. more were siphoned off A rock bass 

 lived in this one hour and twenty minutes. Another fish lived six hours 

 in it when air was made to bubble rapidly through it. The third and 

 fourth withdrawals of 800 c.c. each were thrown away. 



June 2ist. The larva of an aquatic insect lived twelve hours in the 

 extract drawn off for the fifth time : vorticellae lived twenty hours, limi- 

 colous worms twenty hours, a pond snail seventy hours. The sixth and 

 seventh withdrawals were thrown away. 



June 27th. The eighth withdrawal of 800 c.c. made b}- soaking the 

 pine eighteen hours, killed a perch in three hours, and three black bass 

 fry in half an hour. 



