[HARRISON & KENNEDY] DISCOLOURATION OF CODFISH 131 



pH 4.0 — No growth in any of the eight tubes, 



pH 4.4 — No growth in any of the eight tubes. 



pH 4.8 — ^No growth in any of the eight tubes. 



pH 5.2^ — No growth in any of the eight tubes. 



pH 5.6 — Growth in five out of eight tubes. 



pH 6.0- — ^Growth in all tubes. 



pH 6.4 — Slight growth in all tubes. 



pH 6.8 — Slight growth in all tubes. 



pH 6.8 — ^Slight growth in all tubes. 



pH 7.2 — Growth in five out of eight tubes. 



pH 7.6 — Growth in five out of eight tubes. 



pH 8.0^ — Growth in five out of eight tubes. ■ 



pH 8.2^ — Growth in eight tubes. 



pH 8.6^ — Slight growth in eight tubes. 



pH 9 . — No growth in any. 



pH 9.4 — No growth in any. 



pH 9 . 8 — No growth in any. 



Optimum pH was 6.0. Growth showed in this series in six 

 days, in another series that had growth it did not commence until 

 fourteen days. 



Lime Water Series. — ^In many curing establishments lime water 

 is used as a whitewash. A common practice to remove the red coloura- 

 tion on fish is to rub with lime, and this series was prepared to test 

 the effect of lime on the red organism. 



Varying amounts of a clear saturated solution of lime were added 

 to 16 per cent, salt fish broth in the following proportions: 12>^, 25, 

 33, 50 and 75 per cent, lime water. The pH was determined for 

 each lot. All were then inoculated, incubated at 37° C. and examined 

 at various times, up to 32 days. 



12 H per cent lime pH 8.0 — in eight days all four tubes showed growth. 

 25 per cent, lime pH 8.6 — in eight days all four tubes showed growth. 

 33 per cent, lime pH 9.0 — in eight days one showed growth, in 14 



days all four. 

 50 per cent, lime pH 9.4— no growth in 32 days. 

 75 per cent, lime pH 9.8 — no growth in 32 days. 



Lime is difficultly soluble in water, about 0.1 per cent.— and these 

 results seem to indicate that it has some effect when the pH is over 

 9.4. Evidently this substance has use, as a disinfectant in the form 

 of whitewash, and as a possible means of removing red colour and 

 preventing further red growth on fish, although the labour used in 

 applying it would tend to absorb all profit. As salt codfish is soaked 



