SEA-FISHERIES LABORATORY. 125 
series of changes is well shown in the Tables on pp. 93 and 94. In 
1914 the fishery began in June, when the herring flesh contained 
about 5% of fat. The maximum percentage of fat (35%) was 
observed about the middle of June. Spawning began about 
the end of August when the percentage of fat fell to about 17 %. 
By the end of September the herrings were “ spent,” and the 
percentage of fat in the flesh had then decreased to about 9 %. 
With the completion of spawning the shoals disperse and the 
fishery comes to an end. 
The same series of changes is clearly to be seen in the Tables 
of p. 94, which relate to the fisheries of 1916 and 1917. At 
the beginning of the season the percentage of fat in the flesh 
was about 3 to 4% and then rose to a maximum of about 33 % 
(in August of 1916), and to about 42% (at the middle of July 
of 1917). In both years the herrings became “ full” in Sep- 
tember (maturation of ovaries and testes had been completed) 
and then the fat-contents began to decrease. In neither 
year were actually spawned fish sampled. 
The changes in Proteid. 
Not only does the percentage of fat in the fresh, wet flesh 
vary but that of “ proteid”’ (or nitrogen x 6-25) also varies. 
This is clearly seen in the Tables of p. 103, which give the 
monthly means for 1916 and 1917. The proteid-percentage 
is relatively high at the beginning of the season, then decreases 
and becomes minimal at the time of the maximum of fat-con- 
tents (or of maturation of the gonads), and then rises again 
towards the time of spawning. 
But this is the percentage of proteid calculated on the 
wet weight of flesh, that is, on the sum of the weights of water +- 
fat + proteid + ash, and it is therefore a rather complex 
function. In actual practice the wet flesh was first dried in the 
steam oven, then extracted to remove the fat, then finely 
