When a frost comes it nips up the small tributaries among the 

 hills the water in the river below in consequence becomes more or 

 less stagnant. 



This fact may account for the presence of the disease in rivers 

 which, though flowing towards the sea in different directions, 

 derive their water from high lands at and about the same district. 



4. Overstocking and Overcrowding. 



The next point to be considered is overstocking. 



On this subject the following evidence was given : — - 



" The spawning grounds were crowded in the spring of 1879." 

 (Kith.) 



" The river is overstocked, so is every river where there is a 

 ' c fungus. It is a symptom of overstocking. Rivers will only carry 

 " a certain amount of fish. When you get beyond this, the 

 " disease appears. By overstocking means there is neither room 

 " nor food for the fish." (Annan.) 



" Overstocking is the cause. A river can only produce a certain 

 " amount of fish." (Annan.) 



" The fish became diseased because they had no food and were 

 " overcrowded. The great run of fish to be overcrowded as there 

 " was no fishing. 



" The cause of the disease is overstocking. There are more than 

 " twice as many fish as usual. They were crowded on the 

 " spawning beds, and that was the cause of the disease. Thinks 

 " there is a close connexion between the great run of fish and the 

 " appearance of the disease. 



" The river will only bear a certain number of fish, as land will 

 " only bear a certain number of cattle." (Kirkcudbright Dee.) 



" It was due to the large quantity of fish and deficiency of food ; 

 " it is due in fact to overstocking." 



" The Esk is overstocked as a salmon river." 



" There are too many fish in the water and on the spawning 

 " beds." 



" There are too many breeding fish in the river." 



fC Too many fish go up the Tweed. They get overstocked. 

 " There are too many fish in the breeding season, but two few in 

 " the fishing season." 



ei Overcrowding and the long stay of the fish in the river have 

 " helped to cause disease." 



" The last two years there were no fish in the river in the 

 rt summer but two many in the spring ; the river was overstocked." 



" The Tweed being a late river, the fish consequently had more 

 " severe weather to contend with. The pools were overstocked, 

 " and had three times as many fish as usual." 



In considering this matter we must be careful to draw a dis- 

 tinction between overstocking and overcrowding. 



All fish in a river breathe alike by means of gills, therefore 

 whatever kind of fish may happen to be in a river, their numbers 

 all tend to absorb the oxygen from the water, and thus render it 

 less capable of sustaining animal life. This point may be well 



