88 Flow to obtain it. 
place up again. Swans have been tried on some waters, and 
where they can reach it they make havoc amongst it. There are 
places in which it has appeared suddenly without any apparent 
reason. In such cases it has probably been carried by birds. 
The Axacharis was originally introduced into this country 
from America, and is usually looked upon as the most free 
growing plant we have in our waters. There are some native 
plants that are as bad, if not worse, and one of these is the water 
milfoil (AMyriophyllum), which scatters its seeds profusely, and 
springs up, sometimes all over the bottom of a pond, and in a 
very short time spoils the fishing—indeed, I have seen it so 
densely matted together that it was with difficulty that a boat 
could be pulled through it. In such a case the simplest plan of 
dealing with it is to cut it down and drag it out, and where it 
becomes an excessive annoyance the best thing that can be done 
is to run the pond dry, and when the bottom is sufficiently free 
from water, to cultivate it roughly, and take a crop of grass off it 
for a season or two. The advantage of this course is very great, 
as the grass is not absolutely killed at once by the water when 
the pond is refilled, but continues to grow for some ume. The 
conditions existing are very favourable for the production of a 
great mass of animal life, consisting of minute organisms, which 
are multiplied enormously for awhile, and the fish thrive on them. 
In one way or another this experiment has now been often 
involuntarily repeated, and the result proved beyond a doubt, by 
the improvement of the fish themselves. Water plants are a great 
help in the growing of young fish, and in a pond well stocked 
with proper vegetation, trout fry will thrive where fish from the 
same batch of ova, kept in a bare pond and fed artificially, will 
sicken and die in large numbers. This fact alone may be taken 
as a fair test of the value of proper aquatic vegetation. As to the 
best plants to make use of, opinions may differ as yet, but one 
important point to be observed is the avoidance of those the 
introduction of which is likely to prove an annoyance rather than 
otherwise. About the margins of a stream, and at the point 
where it enters a pond or lake, experience has taught us the 
cultivation of the common water-cress (JVasturtium officinale) is 
highly beneficial. There are many terrestrial plants also, which 
