1 9 1 1 - 1 9 1 2 . ] Elimination of A Igce in Lochs and Ponds. 42 5 



not prove a success. " The method of applying the copper 

 by means of dissolving it directly in the beds was next tried, 

 and the success of the treatment was almost immediately 

 evident. In this case the amount of copper added was about 

 equal to a strength of 1 to 50,000,000 parts of water, but it 

 is probable that by the time it reached most of the Spirogyra 

 it was considerably weakened, as it was impossible to prevent 

 a slight current of fresh water from passing through the beds 

 at all times." ^ 



It was soon found that the tonic concentration of copper 

 sulphate varied greatly for different genera of Algse. and even 

 for different species in the same genus. Thus Anahcena was 

 killed off by a strength of 1 part to 10,000,000, while 

 Oscillatoria required 1 to 5,000,000. As to the probable 

 results when copper is taken into the human system, this 

 is a point on which there has been, and still is, a great 

 diversity of opinion, but it does not call for discussion here, 

 seeing we have to do with lochs and ponds only, and not 

 with civic water-supplies. It is confidently affirmed, however, 

 by many authorities, that the quantity of copper necessary 

 to kill off Algse in reservoirs is so infinitesimal that no 

 harm to human beings can possibly result. 



The baneful effects of the presence of certain Algse in the 

 reservoirs of America, and the efforts which have been put 

 forth to combat the evil, have been here rehearsed at some 

 length. This has been done for the twofold reason, — that the 

 recital is interesting and instructive in itself, and because it 

 was from the information thus gained that the particular 

 experiment now to be described was undertaken. Having 

 learnt what had been achieved in the United States by the 

 use of copper sulphate in clearing the water-supplies of 

 Algse, Professor A. S. Pringle-Pattison of Edinburgh Uni- 

 versity, proprietor of The Haining, Selkirk, determined to try 

 the same remedy on the loch in front of his mansion-house. 

 From the paper read by me to the Society last session, 

 members may recollect that a species of Oscillatoria has been 



1 U. S. Department of Agriculture — Bureau of Plant Industry, Bulletin Xo. 

 64 : "A Method of Destroying or Preventing the Growth of Algte and Certain 

 Pathogenic Bacteria in Water Supplies," by George T. Moore and Karl F. 

 Kellerman, p. 26. 



