86 BULLETIN 8, U. S. DEPARTMENT OF AGRICULTURE. 
The damage done to oil sardines by freezing and thawing is negli- 
gible in comparison with that done to mustard sardines. 
The results of these experiments show that it is most desirable to 
store sardines at a low, even temperature. 
DECOMPOSITION OF THE FISH. 
The flesh of fish differs in composition from that of animals in 
that it is relatively richer in gelatin-yielding material (collagen) and 
contains a smaller proportion of extractives. It is probable that cer- 
tain bacteria grow more rapidly on fish than on meat, thus explaining 
the greater rapidity in the decomposition of fish. The end products 
of decomposition of the flesh of fish are the alkaline substances, 
ammonia and amines. Fish flesh contains a small amount of am- 
monia as a normal constituent, and the tissue juices doubtless 
contain amines, but in such small quantities that their presence 
in appreciable amounts may be considered as an evidence of decom- 
position. This is true also of the fiesh of the lobster, crab, and 
shrimp, to which group of marie life the organisms classed as 
feed for the sea herring belong. 
INDICES OF DECOMPOSITION. 
AMMONTA AND AMINES. 
During the course of this investigation a number of determinations 
of the amount of ammonia and amines present in fresh fish and in 
fish at various stages of spoilage were made. Fish free from feed 
and fish containing feed in different stages of digestion, some of them 
belly blown, were examined. The average of numerous determina- 
tions showed that the fresh fish contained from 1.5 to 2 mg of ammonia 
and amines, as nitrogen per 100 grams of fish, or, calculated to the 
water and fat free basis, 11 to 12.5 mg per 100 grams of fish. 
The transportation experiments (p. 26) brought out the following 
facts: In the case of small fish which contained no feed, and were 
kept, without the addition of salt, at 54° C., the viscera and con- 
tents decomposed more rapidly than did the flesh. In the case of 
larger fish, containing a little feed and transported without salt, the 
ammonia and amines in the viscera and contents increased from 12.6 
mg in the fresh material te 22.3 mg per 100 grams of material at the 
end of 12 hours, while that in the flesh increased only from 13 to 
14.5 mg during the same period. After these fish had stood for 24 
hours, the flesh showed a decided change, with evidence of marked 
decomposition. In the case of fish carried in salt (13 sacks per 
hogshead), a noticeable increase in ammoniacai material, from li 
to 18.2 mg per 100 grams, had occurred in the viscera and contents 
by the end of the 4-hdur period of holding. 
Fresh fish containing some feed, but hardly to be classed as ieedy, 
after standing for certain periods of time, showed a marked increase 
