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



June i6th. A perch moribund in eight minutes in a fourth solution 

 from the same sawdust. 



June i6th. A perch moribund in ten minutes in a fifth solution 

 formed by soaking this same sawdust in fresh water for seven hours. 



June 17th. A perch moribund in ten minutes in a sixth solution. 

 With air bubbling through more of this solution, another perch moribund 

 in twenty-one minutes. 



June 1 8th. A perch moribund in twelve minutes in a seventh solu- 

 tion. The water was poured off twice to-day, making an eighth solution. 



June 19th. A perch moribund in eight minutes in a ninth solution. 

 At 1 1 a.m. a pond leech was placed in this solution. It had eighteen 

 young ones, five large and thirteen small, attached to its back. Three 

 of these young at once detached themselves from the mother's back. 

 The adult showed every symptom of discomfort by swimming rapidly 

 round the vessel, then pausing and rolling itself up into a wheel as if to 

 escape the effects of the water. It tried to leave the vessel, but was put 

 back again. Gradually the smaller young detached themselves from the 

 mother until only two or three of the smallest (about % inch in length) 

 remained on her back. The larger young ones were about an inch long, 

 but when extended they were an inch and a half Finally the smallest 

 dropped off and wriggled about with the others on the bottom. The 

 mother came to rest in about three-quarters of an hour. The young 

 were all dead at 4.30 p.m.; the mother was moribund at 6 p.m., and 

 died during the evening. 



Two pond snails lived just twenty-four hours in this solution. The 

 larva of an aquatic insect lived five and a half hours in it. 



At 11.30 a.m. three bunches of vorticellae were placed in the solu- 

 tion. Their cilia at once stopped moving in all the individuals, and they 

 assumed the spherical form. By 5 p.m. most of these animals had 

 dropped from their stalks and lay quite motionless at the bottom of the 

 glass. Apparently they were dead. Returned them to fresh water, but 

 found them all apparently dead next morning. 



A bunch of embryos of the pond snail placed in this extract at 

 5.30 p.m. to-day were all found dead the next morning. 



June 20th. Placed a perch weighing seventy grams in 600 c.c. cedar 



