[HARRISON & KENNEDY] DISCOLOURATION OF CODFISH 113 



grade salt. Cold checked the growth of the organisms and bleached 

 any colour that might be present. 



Browne (27) stated that the development of red colouration was 

 due to the growth of two micro-organisms whose probable origin is the 

 sea salt in which the fish are cured. His summary is as follows: 



1. The reddening of salted fish is due to the growth of two 

 distinct micro-organisms, a spirochete producing an opaque pink 

 colouration and a bacillus producing a transparent red colouration. 



2. These two organisms grow in such close harm.ony that the 

 colouration of fish may vary from the pale pink of the spirochete to 

 the dark red of the bacillus. Likewise their separation into pure 

 culture is very difficult. 



3. The optimum concentration for growth seems to be saturation, 

 growing well on heavily salted fish, brine, sea salt, and fish agar 

 media saturated with sea salt. 



4. No growth appeared on media containing less than 16 per 

 cent, sea salt by weight. 



5. The morphology of both organisms depends upon the con- 

 centration of salt in the medium, varying from the largest forms 

 (14 micra) found in heavily saturated media to the spherical forms 

 (2 micra) found in media of 18 per cent, concentration, with all 

 intermediate forms. The amount and character of the colonial 

 growth does not seem to be afïected by the varying concentrations 

 of salt. 



6. Due to their great sensitiveness to changes in density, staining 

 of these organisms is very difficult. 



7. Their optimum temperature for growth is about 50° to 55° C. 



8. Both forms are strictly aerobic. 



9. Sunlight is not germicidal to these micro-organisms as both 

 will tolerate long exposure (8 hours) to the sunlight or electric light. 



10. Influenced by age, low temperatures, and metabolic products 

 these organisms suffer a temporary loss of pigment which is closely 

 associated with the formation of bodies similar to the coccoid bodies 

 of the spirochetes. By transplantations pigmentation, along with 

 vegetative forms, is resumed. 



11. All results indicate that the probable source of these micro- 

 organisms is the sea salt in which the salt fish are cured and any 

 method devised for the elimination of this reddening from the salt 

 fish industry must be based upon the proper disinfection of the sea 

 salt. 



As it seems important to know whether the organisms isolated 

 by various authors mentioned above can grow in media containing 



8— E 



