160 THE AMERICAN PONDWEED 



not remain permanently rampant, but that after 

 exhausting the soil, it would retire to the bottom and 

 there lie low in the form of a close green carpet until 

 the soil had recovered fertility. Such proved to be the 

 case in Lochleven, which, I understand, is now as 

 fishable as ever. 



But there will come a recurrence of the plague. 

 Elodea first appeared in our lake in 1895 or 1896 (it 

 was first observed in Great Britain in 1847). It 

 speedily took possession, and almost the whole of the 

 water soon presented the appearance of a morass. 

 My notes record that it did not wholly disappear from 

 the surface till the winter of 1906-7. A fresh up-rush 

 took place in 1913, and another in 1918, but on neither 

 occasion did the obstruction last so long as after the 

 first invasion. The sediment in this lake, which is a 

 basin in a tract of good land, appears to recover 

 fertility more rapidly than that of waters covering less 

 generous soil. In hungry Highland lochs the weed 

 may be trusted not to spread beyond such sheltered 

 bays as may have formed a harbour for deposit of 

 alluvium. 



As there are no trout in our lake, only pike, perch, 

 and eels, I can regard with equanimity the interference 

 by these periodical visitations with the contemplative 

 man's recreation, and am more than indemnified by 

 the multitude of wild-fowl, both divers and surface- 

 feeders, attracted by the weed. In ordinary seasons 

 there are plenty of mallard, teal, tufted ducks, poch- 

 ards, and golden-eyes \ but when the weed is up, these 

 are quite eclipsed in number by great flocks of 



