1902-3.] Sawdust and Fish Life. 449 



the stockholders of British Columbia Fish Canning Co's will need to 

 look closely into the future prospects of their industry. 



Norway, or Red Pine. 



Within three minutes, 90 per cent, of the sawdust from this wood 

 had sunk. A strong solution made in eighteen hours rendered a black 

 bass fry moribund in one hour. This water when aerated, but not 

 filtered, rendered another fry moribund in exactly the same time. In 

 both cases the gills of the animals seemed to be affected by fine 

 particles of the wood fibre clinging to the filaments and preventing re- 

 spiration. This was not observed to be the case with any other kind of 

 sawdust. 



A solution made by soaking one gram of this sawdust for nine hours 

 in 250 c.c. of water killed a fry in less than an hour. 



Another fry lived fifteen hours in a solution made by soaking one 

 gram in 850 c.c. water for six hours. 



Oak. 



Contrary to expectations, oak sawdust was not so poisonous as 

 pine and cedar. It communicated an orange colour to the water just as 

 other woods did. A tadpole lived three days in a strong solution, and 

 was quite lively at the end of that time. 



Elm. 



A few experiments were made with elm sawdust. Here again a 

 dense yellowish-brown layer forms at the bottom of the aquarium. 

 This kills adult fish in from half an hour to two hours. A tadpole lived 

 over an hour in it. When this water was thoroughly aerated a perch 

 lived twenty hours in it, and was then active and apparently well. 



Extracts Quickly Soluble. 



The experiments hitherto described would seem to indicate that 

 some considerable time was required for the water to dissolve out the 

 poisonous extracts from white pine sawdust, but such is certainly not 

 the case. This was clearly shown in the following experiment, Fig. 3. 

 Two minnows were confined in a bottle containing 600 c.c. water and 

 eighteen grams of white pine sawdust. Fresh water was made to enter 

 and leave at the rate of 100 c.c. per minute. The inlet tube passed 

 straight to the bottom of the vessel, and its lower end was therefore buried 

 in about an inch of sawdust. One animal lived forty minutes, the other 

 fifty. When the incoming water was reduced to 80 c.c. per minute three 



