112 Flow to obtain it. 
fish dropping down to the screen may be coaxed up stream again 
by judicious and careful feeding, and the screen may then be 
removed for half an hour, so as to allow any that still remain there 
to pass down into the nursery below. The fish often assemble in 
crowds about the embankments and below the pipes, where there 
is an under current as well as at the head and tail of each nursery 
pond. Many of the fish will not remain long in the nurseries at 
all, but never mind if they do not. During the short time they 
have been there they will have received sufficient education to be 
able to look after themselves. We know how they can take care 
of number one in a natural stream, where they have enemies at 
every turn. 
I have often watched multitudes of trout fry dropping down 
our mountain streams in May or June, passing from pool to pool, 
from shallow to shallow, now hiding behind a stone or a tuft of 
water-moss, now passing on carefully but steadily, and feeling their 
way, as it were, all along the course. This they truly do, and ina 
much greater degree than may be supposed, for like the swallow 
leaving us in autumn and returning to the same locality in spring, 
many of these young trout return to the place of their birth. 
There is an instinctive knowledge implanted in a fish, which man 
in his civilized form does not possess, and the more we learn 
about them the more we find there is yet to learn. 
Under proper conditions fry are excellent travellers, and, as 
a rule, two thousand of them will go into the same amount of 
water that would be occupied by about a hundred yearlings. 
This, of course, materially affects the cost. Their safety during 
transit in suitable carriers is almost an absolute certainty. There 
are, of course, contingencies which may arise ez roude which are 
sometimes distressing to the little fish, but these are found 
practically to be of very rare occurrence. Passing through a 
tunnel with the van windows open will fill it with foul air, some of 
which is taken up by the water. Two or three late passengers 
jumping into the van just as the train starts, and smoking there 
during the whole of a long-run, also makes a very trying dispensa. 
tion for the fish. These occurrences formerly took place, but 
now such large quantities of living fish are travelled over the 
railway systems of this country, that their requirements are better 
