NINTH ANNUAL MEETING. 27 
duced almost to certainty if the temperature limits are rigidly 
observed ; but the situation becomes exceedingly perilous if the 
water containing the shad gets very cold, or the water contain- 
ing the trout becomes even moderately warm. Here I wish to 
mention, by way of a caution, a fact that I have only recently 
noticed, and that is that fishes not only increase the warmth of 
the water that they are carried in, but the warmer the water be- 
comes the more their presence increases the warmth. For in- 
stance, in carrying any fish, if you let the temperature rise five 
degrees without checking it, it will rise the next five degrees 
much quicker, and the next five very much quicker still. Ifa 
tank of large trout stands at 4 deg., it shows no marked tenden- 
cy to rise in temperature, but let the temperature-go up to 65 
deg., and it will go on to 70 deg. with surprising rapidity unless 
it is checked. This is natural enough, as the increased heat pro- 
duces a corresponding increased rapidity in the breathing of the 
fish. This creates greater animal heat, which in turn shows 
itself immediately in its effects on the water. It is very well to 
bear this fact in mind when travelling with fishes, because if not 
aware of it, the temperature at which the fishes are kept will, if 
rising, sometimes rise beyond the fatal limit before the attendant 
is conscious of danger. 
(7.) Irregular aeration of the water is a very common though 
a very thoughtless source of loss in transporting fishes. This 
is a fault which no experienced person ought to be guilty of, 
and yet I think it is not an uncommon one. egzz/larity in aera- 
ting the water is what is needed, and not an alternation between 
extreme zeal and reckless neglect, which is just as fatal to the 
fish as thoroughgoing neglect. For instance, if you are carry- 
as 
ing a tank of trout at a temperature which requires aeration 
every fifteen minutes, of what avail is it to aerate the water every 
minute for forty-seven hours, if during the last hour you let them 
go uncared for? The effect is no less fatal than if you had not 
aerated the water at all. Yet the ignorance of this simple fact, 
which every fish-culturist really knows, has been the cause of 
many deaths to the unfortunate fish. The best way is to ascer- 
tain just how often the water in each tank needs aeration, and 
