106 THE SCIENCE OF DRY FLY FISHING. 



as acting as filters and natural purifiers of the waters in 

 which they exist. The Ephemeridae and other water insects 

 are always plentiful in weedy rivers. The fresh water shrimp, 

 one of the principal foods of the trout, abound and multiply 

 amid the shelter of the weeds. 



He must also take into consideration the valuable effect 

 which the water plants have in checking the down stream 

 flow of the water in the dry seasons, and by this natural 

 damming action, keeping a plentiful supply of water in streams 

 which would otherwise soon run very low. (See Plate XXIII.) 



Weed cutting and dredging should always, therefore, be 

 restricted within reasonable limits. 



The only water on the Colne, near Uxbridge, with which 

 I am acquainted, is, in my opinion, thoroughly ruined by the 

 unthinking action of the Thames Conservancy, who, at the 

 most inopportune time of the year, absolutely plough the river 

 bed entirely clear of weeds, leaving it shelterless, foodless, and 

 fishless, save for a few stray fish which may be lucky enough 

 to escape death, mutilation, or banishment, but which soon 

 fall victims to the nets of the local poachers. The hirelings 

 of the Thames Conservancy either do this through ignorance, 

 or, as some of the club men suggest, with the more selfish 

 view of forcing the trout down stream into their own or other 

 water. 



This wholesale weed destruction does not, however, do 

 any good to the Thames or the Thames Conservancy, as, 

 instead of the weeds being left in the Colne to check the 



