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SEA-FISHERIES LABORATORY. 103 
Manz Summer Herrings: Fisheries of 1916 and 1917. 
Composition of the flesh of the fish. Monthly means. 
Energy 
Date. Condition. | Water. Oil. |Proteid.| Ash. Total. | Values. 
1916 
May Warpin. .....: 75:0 2°5 21-1 2°3 100-9 1,100 
June Filling ...... 66-1 11-4 18-6 2-0 98-1 1,806 
July » 55°8 21-6 18-4 2-3 98-1 2,762 
Aug. 4-Full ...... 48-4 31-5 16°5 2°3 98-7 3,608 
Sept. BN, eis cieine om 51-9 25-2 17-3 2-6 97-0 3,050 
1917 
May ... Virgin ...... 68-5 54 | 19-7 3:3. | 96-9 | 1,330 
wome... Pilling ...... 49-0 26°3 20-3 3°7 99-3 3,279 
el 43-6 35°5 16-1 2°6 97-8 3,959 
Aug. _ 43-5 36-6 15-7 2°9 98-7 3,943 
Sept. Ba Hi gy 0 44-1 34-0 17-5 1-7 | 97-3 | 3,876 
This table shows the remarkable variation in the chemical 
composition of herring flesh. Proteid, it will be seen, varies 
from about 152° to 21%, but even this is much less striking , 
than the variability in the fat. This rises from about 23% at 
the beginning of the season, to over 35% at about the time of 
maximum sea temperature, at which time the fish are becoming 
‘* full” and are not far from the spawning phase. In 1916 and 
1917 the spawning time was relatively late in the year, Sep- 
tember, and possibly October, and the fishery ceased on account 
of bad weather before samples of spent fish could be procured. 
In 1914, however, spawning occurred early in September, and 
spent fish were thus obtained, when it was found that the percent- 
age of fat had been reduced to about 9%. No doubt it decreased 
still further as the sea temperature fell and the shoals dispersed 
after spawning. 
We consider the purely physiological aspect of these 
changes later on (but only in a preliminary way). Mean- 
while something must be expected to be said about the 
Energy-value of herring-flesh. 
“ Energy-values”’ are really what chemists call “ heats 
of combustion” stated in a certain way. “ Heat of com- 
