22 BULLETIN 908, U. S. DEPARTMENT OF AGRICULTURE. 
The gills and digestive tract harbored bacteria as long as feed was 
present, but apparently as soon as all feed and waste products were 
eliminated these portions freed themselves of bacteria. Portions of 
cod, rockfish, bass, and alewives were also examined. The alewives 
alone were obtained with no feed present, and out of 72, 47 con- 
tained neither feed nor bacteria. 8B. cola and B. Walfischrauschbrand 
were isolated from the cod. The flesh was free from bacteria in 
practically every instance. 
CHEMICAL COMPOSITION OF THE FEED OF HERRING. 
The crustaceans, to which group of sea life the feed of the sea her- 
ring belong, differ in composition from meats and fish in having a 
large proportion of the carbohydrate glycogen present in the liver. 
This is suggestive in connection with the rapid formation of gas 
observed in decomposing feed, such as schizopods and copepods. | 
Undoubtedly the composition of the feed is of such a nature as to 
furnish an excellent medium for the growth of gas- and none 
ducing bacteria. 
In an investigation of the chemical composition of plankton, K. 
Brandt (4)- obtained the following results on analyzing material which 
consisted almost entirely of copepods: 
TABLE 5.—Chemical composition of copepods (dry basis) (Brandt). 
Per cent. 
IPROheins 550 6 Se ey ae a Sas ee ae See ees eee 58. 80 
Wis bce gigantic eas ak SS A ae ig ag ee as ee 7. 40 
Carbohydrates (by difference)...22< 5552 os 5 ee ee 22. 88 
Ss | 1 Wa ape ae Ree ag aoe -n REAPS Y en ne CA tae mc Mey RE ee ce ae 10. 92 
Composition of ash: 
Silica: (Si@s)-28 2.2. BOTT 2 eas Sy: Siig ees Cora ce 253K 
Common salt (Na@l)-2 =22 22) se Aes ee a ee 1.49 
Other isallis.-e:2 Se eee ree ho ee “AZ 
He found the composition of the dry substance of copepods, which 
included varieties taken from fresh water, to be as follows: 
TABLE 6.—Average composition of copepods (dry basis) (Brandt). 
Per cent. 
SPREOBE UM so aa ge ea ce a 59. 0 
Gian 2 | ee ee ee ee eee ee 4.7 
eaters bear Se ck ee ea oe cope ee ee 7.0 
Carbohydratessc ~ . 22 05s See ee ee eee 20. 0 
NG ie ian gen ee oS a AR pape «re ee are ee rae aoe 3.3 
The results of the chemical analyses, made during this investigation 
on the feed of the sea herring, to determine the rate of decomposition 
are given in Table 7. The total volatile nitrogen, ammonia, and 
amines were determined as the indices of decomposition when the 
feed, copepods, and schizopods were allowed to spoil under the most 
favorable conditions in an incubator. The determination of the total 
