[HARRISON & KENNEDY] DISCOLOURATION OF CODFISH 121 



On discoloured fish the organism is found as a sphere or as a 

 cylindrical rod, varying in size. Temperature at which the fish 

 have been kept and the amount of salt present in or on the tissues 

 seem to be the determining factors, and of these two the latter exerts 

 the greater influence. Higher temperatures and larger salt con- 

 centration as a rule increase the size. Whilst this organism, which 

 we propose to call Pseitdomonas salinaria, is found on cured salted 

 codfish, it originated in all probability from sea water. Six samples 

 of brine of different strengths of concentration have been received 

 from Turks Islands. These range from 10° salinity (sea water) to 

 100°, the crystallizing point, arid from all these, including the sea 

 water, we have isolated and studied the red organism. 



Further particulars concerning these results will be found on 

 page 147, but here we wish to emphasize the importance of the gradual 

 increase in salinity, an increase of 30° salinity in about twenty days, 

 and the presence of the vegetable matter which provides the organic 

 nutriment needed by the organism. In the 40° brine we find the 

 organism as a round body, 2-3 /x in diameter, with a clear, double, 

 contoured membrane in unstained preparations, and inside of this 

 slightly granular and pink mass, frequently with a darker spot present. 

 On staining with Giemsa the membrane stains deep violet, the granular 

 content not at all, and the darker spot taking a little colour. Cells 

 of this character are often formed in stronger brine solutions, on fish, 

 and in other culture media. 



This spherical form then is the first shape which is encountered 

 in the natural habitat of this organism. As water gradually evaporates 

 and salinity increases the osmotic pressure must increase, but the 

 change being gradual the cell seems able to accommodate itself to 

 these changes, until the point of crystallization is reached when the 

 salt content is about 35 per cent. The organism is now found not 

 only as a sphere but as a cylindrical rod, and if at this stage it is 

 brought into contact with water, it immediately collapses (plasmo- 

 ptysis) and breaks up into a slimy amorphous mass. With salinity 

 ranging between 15 and 20 per cent, of salt by weight the organism 

 is found as a round, oval or amoeboid form, accompanied by short 

 rods of all shapes. Growth at this stage seems partly by fission, as 

 stretching may be observed with a lighter area, indicating where the 

 membrane is forming, and partly by budding, as figure 8 forms with 

 one half smaller than the other, or attached somewhat to the side 

 and not at the apex of elliptical cells, and occasionally two buds 

 coming from a single cell may be observed. At this stage of growth 

 the cells take the stain (either Giemsa or aniline carbolic Gentian 



