1902-3]. Sawdust and Fish Life. 439 



Pulp Industry. 



There are other industries in Canada, which in preparing their 

 products for market grind up plants and trees, and thus let out their 

 cell contents. One of these is the pulp industry — likely to become very 

 extensive in the near future. Two processes are in vogue in this indus- 

 try. In one, the logs are macerated with chemicals, the mills being 

 known as sulphite mills. In the other process, the logs are ground into 

 shreds in what are known as mechanical mills. Both processes liberate 

 the greatest possible quantity of stored material from the wood cells, 

 and if this material is equally poisonous with that liberated from saw- 

 dust, then the waste water discharged from a pulp mill should be much 

 more poisonous than from a sawmill. The St. Andrew's experiments 

 determined the percentage of poison from a sulphite mill which is fatal 

 to fish life, but, so far as I know, the percentage of poison from a 

 mechanical mill has never been determined. A provisional conclusion, 

 however, may be based upon some of the experiments to be described 

 later in this paper. 



Beet Sugar Industry. 



The manufacture of sugar from the maple and from the beet 

 depends upon the fact that sugar is one of the reserve materials stored 

 in the cells of these plants. In order to liberate the sugar from the beet 

 roots they must be thoroughly ground into a mash, so as to rupture the 

 cell walls. The more effectively this is done, the higher is the percent- 

 age of sugar obtained from the beet. It is easily conceivable that the 

 water that escapes from beet sugar factories may contain matter that 

 is poisonous to fish life. 



Professor Prince called attention to both these sources of pollution 

 in his report for 1 899, and they are referred to now merely for the pur- 

 pose of emphasizing the fact that other industries may pollute the 

 streams of Canada to even a greater extent than lumbering. In all 

 three industries the source of pollution is the contents of the wood or 

 plant cell. 



There is a similar action going on in nature all the time. Leaves, 

 branches, and trunks of dead trees are decomposing continuously ; their 

 cell contents are being dissolved in rain and melting snow, and are in 

 part carried away in streams and rivers. The only difference is that in 



