78 BULLETIN 908, U. S. DEPARTMENT OF AGRICULTURE. 
third amines. During storage at room temperature the proportions 
appeared to change slowly, until after a long period of standing the 
total alkaline material was about half ammonia and half amines. 
When stored at a temperature just above freezing, the total quan- 
tity of volatile alkaline materials was greatly reduced, as compared 
with that produced at ordinary temperatures. 
Sardines stored just above a freezing temperature for 32 months 
contained in most cases less volatile alkaline material than was 
found when they were held at room temperature for a period of 15 
months. The relative amounts of ammonia and amines formed at 
the lower temperature of storage remain the same as the total vola- 
tile alkaline material formed while standing at room temperature. 
The total amines composing this volatile alkaline material consisted 
mostly of triamine (practically 80 per cent). Monamine and diam- 
ine also were present during the earlier period of storage(15 and 18 
months), but in much smaller quantities. At the end of the 32- 
month storage period no monamine was found, but the diamine in 
some instances had increased 50 per cent or more. The difference 
in the rate of formation of ammonia-and of amines at a lower tem- 
perature of storage and at room temperature suggests that these 
changes may be caused by bacterial growth, although it is more 
probable that this action is associated with detinning and adsorp- 
tion. of tin by the fish protein. 
When tke cans of long standing commercial packs were opened 
the fish constituting the 4- and 6-year-old goods were decidedly soft. 
These showed the presence of the largest amounts of amine. 
The quantity of ammonia and amines in the canned sardines an 
has a decided bearing upon the detinning of the interior of the cans 
(p. 82). 
It is planned to continue the studies on the relation of detinning 
to the formation of ammonia and amines in canned fish. 
Errect oF FREEZING AND THAWING ON SARDINES. 
To determine the effect of freezing and thawing upon sardines, 
cans from each of the packs put up under the drying experiments 
(p. 51) were frozen and thawed, after which they were compared 
with cans of the same goods which had not been frozen. Three lots 
were employed. In one the sardines were frozen and thawed twice, 
in another three times, and in the third six times. 
The general appearance of the oil sardines which had been frozen 
two, three, and six times was practically the same as that of the fish 
which had not been frozen. On closer examination, however, cer- 
tain changes in the texture of the meat were readily recognizable. 
It was apparent that the texture of the fish which had been insuf- 
ficiently dried was partially destroyed when frozen and thawed twice, 
