CHEMICAL COMPOSITION OF FOOD-FISHES. 
687 
v loss resulting from this was small, so that, though the figures repre- 
« t somewhat less than the actual amount of edible portion in the 
cimens, yet the amount thus wasted was doubtless less than would 
left unconsumed at an ordinary table. 
’he reasons for rejecting the skin, which generally has considerable 
ritive value, were that its chemical constitution is different from that 
the flesh which we wished first of all to study, and that circum- 
nces forbade our entering into the examination of the tissues other 
m flesh, valuable as their study would be. Nor is this omission en- 
3 ly without warrant even from the economical standpoint, since, so far 
I have observed in this country, the skin is not usually eaten. With 
» closer domestic economy that increased density of population must 
' ing, people will become more careful to utilize such materials. 
DRYING. 
Partial drying . — In each case one or more samples of 50 to 100 grammes 
each, selected from different portions of the freshly chopped flesh, were 
weighed on a watch glass or small sauce plate and heated from 24 to 48 
hours in an ordinary drying oven at a temperature of about 96° C., in a 
current of dry hydrogen. They were then allowed to cool and stand 
in the open air, but carefully protected from dust, for about 12 hours, 
when they were again weighed, pulverized, sifted through a sieve with 
circular holes .5 mm. in diameter, bottled, and set aside for analysis. The 
material in this condition constituted what was termed the “ partly 
dried v sample. A few of the fattest samples, however, could not be 
worked through so fine a sieve. For these either a coarser sieve was 
used or the substance was crushed as finely as practicable and bottled 
without sifting. 
Drying in hydrogen and in air . — The especial object in drying in 
hydrogen was to prevent possible oxidation of fats, whereby the latter 
'ould be rendered insoluble in ether or the accuracy of the calcula- 
ons impaired. That this is at all necessary in animal tissues, or when 
: is necessary and when not, 1 am not prepared to affirm. In the early 
art of the work we arranged an apparatus for drying in hydrogen as 
precaution, and although comparative trials in air and in hydrogen 
iid not show large differences in results, the apparatus was so conven- 
3nt that we have used it throughout the investigation in the partial 
rying of the material to be used in the determination of water, fat, 
itrogen, and ash. 
As drying in air is more convenient for larger quantities and answers 
•erfectly well for certain determinations, as sulphur, phosphorus, and 
hlorine, a sufficient quantity of material for these determinations was 
•repared by drying in air. This was effected by weighing 200 grammes 
r more of the freshly chopped substance at the same time that the 
ortion was taken for the drying in hydrogen. With the exception 
