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



Maple Sawdust. 



A dark orange liquid oozed out from maple, and lay at the bottom 

 of the aquarium. This was separated from the clear liquid above by a 

 perfectly well-defined greyish surface. At the top of the water (i6j4 

 inches deep) intake and outflow pipes allowed tap water to flow into and 

 out of the aquarium at the rate of 600 c.c. per minute. A perch having 

 sunk into this extract once or twice could not afterwards be driven into 

 it. The animal soon found where the fresh water inlet was, and when 

 driven to other parts of the aquarium would always come back to the 

 fresh water. 



Aquatic plants in maple extract lost their chlorophyl in three days. 

 Returned to fresh w^ater they regained their colour, but the tips of their 

 leaves had died. 



Hemlock Sawdust. 



Hemlock has always had a bad reputation, but does not deserve it. 



On July 27th, six black bass fry were placed in a mixture of five 

 volumes of water to one volume of hemlock sawdust. The vessel was 

 covered with four layers of cheese cloth, and a copious stream of water 

 was made to fall upon it from a tap about a foot above it. The fry 

 were all alive and well at the end of three days, when they were returned 

 to the aquarium. 



As a control experiment, five black bass fry were kept for the same 

 length of time in the same volume of water, viz., 6(X) c.c, with air 

 bubbling through it all the time. These animals also were quite lively 

 and well at the end of the experiment. 



British Columbia Cedar Sawdust. 



This sawdust sank rapidly, 75 per cent, falling to the bottom of 

 perfectly still water in two minutes. It gave ofl" a very poisonous 

 extract. Two black bass fry lived only one minute in a solution made 

 by standing five and a-half hours. The colour was a beautiful amber 

 with a strong smell of cedar. A solution made by one gram of saw- 

 dust standing in 500 c.c. water for three hours rendered a black bass 

 fry moribund in two hours. A solution from one gram in 750 c.c. water 

 for twenty-seven hours, killed another fry in two and a-half hours. 

 Even as homeopathic a solution as one gram in 1,500 c.c. killed fry in less 

 than eighteen hours. 



If much of this sawdust is poured into British Columbia streams, 



