244 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [14] 
always necessary before such an investigation can be got into good 
running order, and adding to all this the importance of studying the 
mineral ingredients, it is clear that a great deal of labor will be necessary 
to reach the desired results. 
Cold-water extract.—Of the freshly-chopped substance 334 grams were 
digested for 18 to 24, generally about 20, hours, in 500° of cold water, 
and filtered. 
The filtration was conducted at first through “coffee filter paper.” 
Later Messrs. Woods and Beamer found it better to use fine linen cloth, 
which has the advantages of more rapid filtration and of allowing the 
liquid to be squeezed through with proper care. The solids do not pass 
through the cloth more than through the filter paper, and by laying on 
a glass plate, scraping, and subsequent rinsing, they are separated 
much more easily and completely than they can be from the filter paper. 
Albumen.—The filtrate thus obtained was boiled and filtered through 
previously dried and weighed asbestos filters. After washing with ether, 
the filter, with its contents, was dried and weighed. That this method 
for determining the albumen is accurate, is by no means proven or even 
probable. But we find that treatment with acid, as acetic acid, in the or- 
dinary way, instead of increasing the amount coagulated is very apt to 
hinder coagulation and sometimes to prevent it altogether, while boiling 
the extract alone invariably produces coagulation. Very likely precip- 
jtation by alcohol, ferric acetate, or otherwise, might insure more com- 
plete separation of the albumen. 
Hatractive matters.—The filtrate from the coagulated albumen was evap- 
orated in platinumeapsules and weighed. One sample was used for deter- 
mination of the ash, which was done by charring at a low temperature, 
extracting with water, igniting the residue until it was well burned, 
adding the water solution, evaporating, igniting carefully at a low tem- 
perature, and weighing. The other sample was finely ground, dried in 
air to determine the percentage of water, and extracted with ether until 
free from fat, usually two or three hours. The crude extract, minus the 
water, fat, and ash, is reckoned as pure extract, and is designated in 
Tables I and II as “ Extractive matters.” It of course contains any al- 
bumen which may not have been coagulated, the other nitrogenous com- 
pounds, the carbohydrates, and whatever else, except fats and mineral 
matters, was taken from the flesh of the fish by the digestion in cold 
distilled water. 
Hot-water extract—“gelatin.”—The residue left after the extraction 
with cold water was treated for 18 to 24 hours, generally about 20 hours, 
with distilled water at 100° or slightly below. It was then filtered 
through weighed asbestos filters, and the filtrate evaporated to dry- 
ness in platinum, and weighed as crude gelatin. In this, fat and ash were 
determined, and the pure extract called in the tables “gelatin,” esti- 
mated as in the cold-water extract. It should be stated that in both 
hot and cold water extracts the figures for total extract in the tables 
si 
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