56 COD AND OTHER SALT FISH FOR THE MARKET. 



gelatin, the solid gelatin forming a thin rim on the outside. The 

 gelatin darkens. 



Bread paste. This is a good medium ; the organism covers the sur- 

 face and pushes down along the sides. In eight days it is very dark, 

 later becoming a solid black mass. 



Tomato bouillon. In three days many colorless colonies are formed 

 along the sides of the tube and in the bottom. Later a layer forms on 

 the surface, which darkens as it ages and hardens, so that it is difficult 

 to separate. The liquid remains clear but darkens. The submerged 

 colonies remain colorless. 



Sea-salt gelatin. In this medium the development is slow, the 

 mycelium forming slowly on the surface, and darkening gradually. 

 The gelatin is liquefied and darkened, though it remains clear. 



A gar plus salt. In agar plus 5 per cent salt the growth is uncer- 

 tain ; sometimes a thin line of separate colonies forms along the streak, 

 and then development ceases. Sometimes no growth takes place. 

 With larger amounts of salt no development occurs. 



TEMPERATURE TESTS. 



When agar and gelatin were inoculated and placed in the refriger- 

 ator, the temperature varying from 44 to 50 F., a tiny spot devel- 

 oped at the puncture point in six days, no further development 

 taking place. At 72 the agar had one-third of the surface covered, 

 and was black ; the gelatin had a still larger layer of mycelium, and 

 about three-fourths of the gelatin liquefied. At 90 F. no develop- 

 ment took place in either medium. 



INFECTION EXPERIMENTS. 

 INOCULATIONS. 



When red fish were received from the factory, pieces of fresh fish 

 were inoculated directly from the reddened spots to determine the 

 time required for the reddening. The pieces were placed in covered 

 glass dishes and kept at a temperature of approximately 20 C. In 

 ten days a perceptible pink layer had formed, which spread gradu- 

 ally. As the fish dried, salt crystals formed on the surface, but the 

 reddening increased. A foul odor developed even when a small 

 amount of reddening was present. 



At first, inoculations were made from the coccus, as that was the 

 only organism which produced red color. Afterwards the bacillus 

 and mold were used, and also the coccus and bacillus together, and 

 these two with the mold. In the earlier inoculations, fish which had 

 been sterilized by heating in the steam sterilizer was inoculated, but 

 the fish spoiled by softening and became foul before the germs 

 causing the reddening had time to develop. The raw fish was then 

 used exclusively ; large pieces from the tablets were selected, the sur- 



