PRESERVATIVES; 39 



use steam at sonic places nor at all times, and some other agent is 

 needed for supplementary use. Whitewash is good, and has a place 

 as a disinfectant for the woodwork, walls, and ceilings. Sulphurous 

 acid can probably be employed wherever the whitewash can not be 

 used and as a substitute for steam when the latter is not available. 



Tests were made of the disinfecting power of concentrated sul- 

 phurous acid as it is purchased in the open market. These consisted 

 in adding one-sixth, one-fourth, one-half, 1, 2, 3, 4, 5, and 6 per cent, 

 respectively, to sea water and beef broth gelatin, which was inocu- 

 lated with the bacillus, the coccus, and the brown mold. The bacil- 

 lus and coccus were checked, though not killed, in tlie solutions con- 

 taining one-half per cent of the acid or less. They were killed in 

 the 1 per cent solution. The mold was more resistant as growth took 

 place, but it was delayed in the 3 per cent solution, and was killed by 

 the 4 per cent solution. 



Tests were also made by spraying the woodwork and kench racks, 

 which had reddened to a greater or less degree, with solutions of the 

 acid. Where growth was very abundant a solution of 1 part of the 

 acid to 50 parts of water was effective, and where it was less pro- 

 nounced a solution of 1 part to 200 worked well. On the butts, kench 

 racks, floors, etc., a solution of 1 part in 100 is recommended, and for 

 the carrying boxes, table tops, etc., 1 part to 200 ; the dilution might be 

 carried further after repeated use has been made of it. After a. ves- 

 sel has been unloaded, burning sulphur in the hold will have the 

 same effect as spraying. Precautions should be taken, however, to 

 remove any excess of sulphurous acid from the room before the fish 

 are handled or stored in it. 



PRESERVATIVES. 



Boracic acid was introduced as a preservative in the fish industry 

 in 1881 and was used continuously until 1907, when it was superseded 

 by sodium benzoate. The boracic acid is still used on some of the 

 export fish, and is regarded as the best preservative for the purpose. 

 It is applied to the fish when they are being shifted in the waterhorse 

 or to the outside of the completed cake. It was also used in the 

 kenches in the storeroom to prevent spoilage. The quantity of the 

 acid used was not generally known, though it was agreed that its use 

 had been abused. 



Since 1907 sodium benzoate has taken the place of boracic acid. 

 The sodium benzoate is mixed with finely ground salt and applied by 

 means of a powdering can like a large pepper box. It is used upon 

 the fish in the storeroom if the weather conditions demand it, but its 

 principal use is upon the fish as they are being weighed out into tab- 

 lets. r Fh is preservative is used chiefly from March 1 to November 1. 

 The amount used is not weighed, but is dusted on to cover the whole 



