BACTERIAL DECOMPOSITION OF SALMON 355 



lot in each case was a preliminary experiment and the bacterio- 

 logical examination was not usually conducted on more than the 

 first one or two days. Only one lot of silver and chum salmon 

 was examined. The temperature on the days on which the fish 

 were held never fell below 50° F. nor rose above 70° F. 



In the bacteriological examination of the fish total counts of 

 bacteria were made from the muscle tissue of the back and belly 

 of the fish and agar slant cultures were made from various parts 

 and organs of the fish including the mouth, gills, stomach, ceca, 

 intestines, heart, liver and kidney. Cultures in lactose broth 

 fermentation tubes were made from the stomach, ceca, and 

 intestines. 



Since the work was necessarily often done in the field at con- 

 siderable distances from the laboratory, some difficulty was ex- 

 perienced in the plating of the muscular tissue for total count 

 but the technic used, in general, worked very well. The body 

 of the fish was thoroughly washed with alcohol and the alcohol 

 burned off. With instruments sterilized by flaming in alcohol a 

 small flap of skin just posterior to the dorsal fin was carefully 

 lifted and pinned back. A piece of muscle weighing approxi- 

 mately one gram was transferred to a sterile flask of known 

 weight. The flasks used were of thick-walled, heavy glass in 

 order that they might not break under the vigorous shaking 

 necessary to break up the tissue. Known amounts of sterile, 

 broken glass and sterile NaCl solution were added and the whole 

 vigorously shaken until the tissue was thoroughly broken up. 

 This suspension of tissue was diluted and plated according to 

 the usual methods. The flask containing the remaining sus- 

 pension was tightly stoppered and saved until the laboratory 

 could be reached when it was weighed and the exact amount of 

 original tissue computed. The sample of flesh from the belly 

 was taken in the same manner just posterior to the ventral fin. 

 Glucose agar was used and all incubations were made at room 

 temperature. ' 



The results of the experiments in determining total count are 

 given in tables 1, 2, 3, and 4. 



