74 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Seventeen haddocks ( Gadus cegelfinus), four flounders (Pleuronectes flesus), 
and two dog-fish (Scy Ilium catulus) were caught. They were hauled up 
slowly, carefully unhooked, and the haddocks and flounders were trans- 
ferred alive to a tank of sea- water in the boat. One hour afterwards the 
temperature of the water and of the fish was recorded. The temperature 
of the dog-fish was taken in the sea alongside the boat before they were 
removed from the line. The temperature of the air was 13° - 2 C., of the 
sea at the surface, 11 0, 8 C., and of the sea- water in the tank, 12°T C. at the 
commencement of the observations, and 12°'3 C. at the end. In the dog- 
fish and haddocks the thermometer was placed in the rectum, and in the 
oesophagus in the flounders. A thick rubber glove was used to prevent 
the heat of the hand being communicated to the body of the fish. The 
haddocks and flounders weighed from J to 2 lbs., the dog-fish about 3 lbs. 
Water. 
Fish. 
1R8 C. 
12-1 
12-3 
Dog-fish 2 11 ’8 C. 
Flounders | g Jg-2 
rZ 12-0 
Haddocks J 4 \l '} 2 
1 4 (dead) 12-1 
In the dog-fish the temperature was the same as that of the water at 
the surface ; and as this sound is always traversed by strong currents, it 
may be taken that the temperature was uniform from the surface to the 
bottom, although no observations were made at different depths on this 
particular occasion. This species is not a ground-fish, but may be found 
swimming at any depth. 
The conditions under which the observations were made on the haddocks 
and flounders were not entirely satisfactory. The water in the tank, 
having been drawn from the sea just before the fish were transferred to it, 
was at first 11°*8 C., but gradually became warmer, and it is not probable 
that the body-temperature of the fish would follow at once the changes in 
the temperature of the water. Richet * found that in the water tortoise, 
when the animal was placed in a medium which was being slowly cooled, 
its temperature at any moment was distinctly above that of the medium, 
and vice versa if the medium was being warmed; that is to say, the 
temperature of the animal lagged behind that of the medium. This is the 
only occasion on which I have found the fish colder than the water in 
* Richet, Did. de Physiol ., vol. iii., p. 106 . 
