126 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
powdered and again dried. The residues were then examined 
for proteid, giving the results :— 
Percentages of (N X 6:25) im various herrings : means. 
Month and Source. _ 1916. 1917. 1918. 
Manx, May 76-4 93-8 
5 eee 78:6 82°5 
» July 78-1 84:0 
. August 78-9 83:5 
.. September 80°5 81-2 
Means 78:5 85-0 
Welsh, November, Mean of 3 samples _.... sini 90°6 
Shop, November _... ee ss er ace 90°5 oe 
>», February aha but Be re Cee Lets 91-9 
Mean a ion ist ty 91-4 
Now it is difficult to see that the variations from month 
to month in the case of the Manx Summer herrings are of real 
significance. Whatever the analytical error in the estimation 
of N may be it is multiplied by 6-25, and so we must regard the 
errors of the percentages of “ proteid’’ in these residues as 
rather high, say 0:5 to 1%. But we may perhaps distinguish 
safely between (1) Manx Summer herrings of 1916, (2) Manx 
Summer herrings of 1917, (3) Winter herrings. Here the differ- — 
ences in the percentage of N x 6-25 lie well outside the 
analytical errors. 
The Proteid Factor 6:25. 
Thus the percentage of (N x 6-25) in the various water- 
free, oil-free residues varies between about 78 and 92, while 
the percentage of non-volatile matter is never more than about 
3. <A balance of about 19 to 5 % is thus left unaccounted for 
by the analyses, and it is always possible that this balance may — 
be represented by reducing substances (‘ carbohydrates ”’). 
