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



it would, therefore, be only in accordance witli well known facts to find 

 that aromatic compounds, some pleasant, some unpleasant, could be 

 formed from pine extracts by the action of different kinds of micro- 

 organisms. 



Some of the bottom water was distilled for the purpose of seeing 

 whether this aromatic compound could be thus separated from the water, 

 but the attempt failed. The distillate had the aromatic odour of the 

 original water, but mixed with it was a disagreeable burnt smell. This 

 distilled water killed minnows in half an hour, both when aerated or 

 unaerated. 



At the end of three weeks the uppermost fourteen inches of water 

 had gradually become a steel grey or slaty colour and was quite 

 opaque. The outlines of a window sash ten feet away could not be 

 seen through it. The extract at the bottom still killed by its vegetable 

 poison ; the slate coloured water above still killed by suffocation. 



At the end of five weeks these conditions were but slightly changed. 

 In place, however, of the pleasant aromatic odour previously arising from 

 the surface, a musty, disagreeable smell had taken its place. As the 

 laboratory windows were always open, mosquito larvae became numerous 

 and appeared to be feeding upon the bacteria. These larvse died in 

 sawdust solutions only when prevented from coming to the surface to 

 breathe. 



The water at the very bottom was still of a yellowish tinge ; the 

 uppermost was smoky or slate coloured, as already explained. About 

 6,000 c.c. of this slate coloured water was siphoned off from the middle, 

 on July 31st, and placed outside of the laboratory in direct sunlight. The 

 object of this was to compare changes taking place in the slaty water 

 placed in sunlight and breeze, with changes taking place in the slaty 

 water which remained in the aquarium. 



Dr. W. T. Connell,Professor of Bacteriology, made cultures from these 

 two waters and compared them on three different occasions. His report 

 which will be found in the appendix to this paper, shows that while the 

 number of colonies from water in the shade increased from 3,435 per 

 cubic centimetre to 7,870 per cubic centimetre ; the number of colonies 

 from water in sunshine increased from 3,435 per cubic centimetre to 

 37,070 per cubic centimetre. These latter were different bacteria from 

 the former. Sunlight and air had killed off those kinds of bacteria 

 which flourish in shade and in absence of oxygen, and had stimulated 

 the growth of other kinds of bacteria which flourish in sunshine and 



