of ike Fishery Board for Scotland. 



19 



putrescible, and, although it contains a certain amount of organic 

 matter, this organic matter is reduced to a stable or unchangeable 

 condition, it takes up oxygen very slowly, being already well 

 aerated, and does not cause any noxious growths. 



At the request of the Commission, I undertook to supervise an 

 experiment expressly designed to test the effect of the effluent 

 upon salmon. A series of tanks were erected at Coleburn Dis- 

 tillery in a small wooden house placed near the Commissioners' 

 plant. In these the ova of salmon, procured through the kindness 

 of the Duke of Richmond and Gordon, were placed, together with 

 the young of salmon at two ages. The tanks were arranged in 

 pairs so that ova and j^oung could be kept separately and each 

 subjected to similar tests. The undiluted effluent was passed 

 through one pair of tanks, a 40 per cent, diluted effluent through 

 another pair, and a 4 per cent, dilution through a third pair; 

 while, as a control, a pair of tanks received simply water from the 

 neighbouring stream. It would be out of place here to describe 

 the detailed results. These will be duly made public by the 

 Commission ; but I am glad, with the permission of the Earl of 

 Iddesleigh, to be able to state generally that the experiment has 

 been a complete success, that the eggs have hatched out in a 

 perfectly normal manner, and that the percentage of deaths has in 

 no way been excessive. The test of eggs and fry in the undiluted 

 effluent was of course far more severe than could possibly be 

 brought about in any natural stream ; yet hatching was as successful 

 in this as in the water tank, while the young fish fed and throve 

 in an almost surprising manner. 



From these results, one seems to me to be justified in affirming 

 with some degree of confidence that this effluent might be dis- 

 charged into a river, or into even a quite small burn, without risk 

 to the eggs and delicate fry of the salmon. I regard the results 

 obtained by the comparatively simple and inexpensive process 

 referred to as of the greatest possible importance in connection 

 with river purification. 



Incidentally, the result shows that the precise quality of nitro- 

 genous matter in a theoretically not quite pure fluid, as ascertained 

 by accurate chemical analysis in a laboratory, has to be taken into 

 consideration as well as the mere presence or absence of certain 

 chemical substances ; that, in other words, a small percentage of 

 nitrogenous matter may be present and may be so reduced to an 

 unchangeable condition as to be practically negligible. 



No result the least approaching that obtained at Coleburn has, I 

 believe I am correct in stating, ever been obtained, and from a 

 salmon-fishing point of view the test by direct experiment has 

 been both ample and satisfactory. This, I venture to think, 

 should be carefully noted not only by proprietors of salmon 

 fisheries, but by the distillers themselves, as well as by other 

 manufacturers and by municipal authorities. 



