INLAND FISHERIES. Ill 



of cases, however, the poisonous bacterial products are not basic, 

 although their true chemical structure is not understood. 



The researches of Meisener Rosenbach, G. Hauser, F. John J. 

 von Todor, and others, have shown that the blood and flesh of 

 healthy animals is entirely free from bacteria. But the contents 

 of the digestive organs are rich in Schizomycetes. (Popoff has 

 shoAvn that the digestive canal of a healthy new-born animal is, at 

 the moment of birth, free from bacteria. These, however, subse- 

 quently obtain access, principally in the food, and the contents of 

 the bowels become extremely rich in microbes.) 



If a slaughtered animal is left without'being disemboweled, these 

 bacteria will make their way through the capillary vessels of the 

 intestinal villi into the arterioles, the alkaline contents of which 

 (rich in albumen) are especially favorable to these acidly putre- 

 factive bacteria, so that the entire carcass quickly begins to 

 undergo decomposition. This early decay may be prevented by 

 the immediate removal of the entire alimentary canal, from oesoph- 

 agus to rectum, and, if this precaution be taken, the flesh will for 

 a time remain free from putrefactive bacteria. If putrefaction 

 afterwards sets in, it is due to the bacteria from external sources 

 obtaining access to the flesh. 



The gradual penetration by way of the blood vessels into the 

 interior of the flesh has been studied bj^ Trombetta and Gartner. 

 Gartner found them only in the external layers of meat three days 

 old ; but at the end of seven days they had penetrated 2 c. c. below 

 the surface. It is, however, probable that the flesh of fish is not 

 so resistant to the penetration of bacteria. The sources of this 

 bacterial infection cannot be entirely removed, but they can be 

 considerably reduced by cleanly procedure, and attempts may 

 be made to restrict the increase of the microbes and thus arrest 

 the process of decay. The most common remedy is cold, but ex- 

 periment has shown that the temperature must be kept some de- 

 grees below zero C. in order to obtain the best results. This 

 method is used not only in the American and Australian abattoirs, 

 but haddock caught in Norway are cleaned and frozen at 50" C, 



