70 Proceedings of the Royal Society of Edinburgh. [Sess. 
This and the deep-sea reversing thermometer were compared by immersing 
them together in a tank of sea-water, and the readings were found to 
correspond. 
Immediately the fish was brought out of the water on to the deck, 
and before being bled, the thermometer was inserted through the cloaca 
into the rectum to the depth of six inches, and allowed to remain there 
till the mercury became stationary. In many cases the temperature of 
the blood was taken. This was effected by severing the gills on one side 
with a sharp knife and immersing the bulb of the thermometer in the 
pool of blood which quickly collected. It is the routine practice of the 
fishermen to bleed each cod in this way as soon as it is brought on board, 
because it improves the appearance of the fish for market. In some cases 
a small incision was made through the skin, and the bulb of the thermometer 
pushed into the thick mass of muscle on the back, behind the pectoral 
fin, to the depth of two inches ; in this way the temperature of the 
muscle was obtained. 
The fish examined varied in weight from 5 lbs. to 25 lbs., but the 
larger specimens were selected by preference. They were brought on 
board frequently in such quick succession that all could not be examined. 
The time taken by a fisherman to haul a 15-lb. or 20-lb. cod from a depth 
of 50 fathoms varied from one and a half to two minutes, and all the 
while it was struggling violently to get free. 
Observations were made as described above on 90 cod-fish ( Gadus 
morrhua), 5 lings ( Molva vulgaris), 1 tusk or torsk ( Brosmius brosme), 
and 1 saithe or coal-fish ( Gadus virens), on five different days. The 
results are given in tabular form for each day. 
September 12, 1907. 
Calm ; bright sunshine ; air in shade, 14 0, 2 C. ; depth of water, 49 fathoms. Flood 
“slack,” 1.30 to 2.30 p.m. ; 71 cod caught, 31 examined. 
Water. 
Fish. 
Difference. 
Fathoms. 
Temperature. 
Number. 
Eectal Temperature. 
5 
11-4 C. 
6 
11°8 C. 
0°6 C. 
10 
11*3 
10 
11-7 
0-5 
20 
11-3 
8 
11-6 
0-4 
30 
11-2 
7 
11-5 
0-3 
40 
11 -2 
48 
11-2 
31 
Mean, 11-65 
0-45 
