of the Fishery Board for Scotlwnd. 1 9 



hours, the gills in all varieties of fish begin to lose their reddish tint and 

 gradually become grey and slimy. This always occurs by the third or 

 fourth day. 



There are, however, certain points which have to be kept in view. 

 In examining quantities of fresh fish, one meets frequently with some 

 which have paler gills than their neighbours, and yet are perfectly fresh, 

 and it is remarkable that in many cases the gills retain with little 

 diminution — especially if washed daily with fresh water or salt water — 

 their characteristic tints, even when the fish has become putrid. It 

 should also be noted that the gills of trawled fish at time of capture, 

 more especially if they have been dragged in the trawl net for some time, 

 are usually of a paler colour than line fish at time of capture. 



8. Smell. 



So long as fish are fresh they retain their characteristic but not dis- 

 agreeable odour ; but when fish begin to decompose through bacteria 

 activity new substances are formed which are often characterised by 

 disagreeable penetrating odours, and often the escape of these volatile 

 bye-products is the first warning that decomposition has set in. 



There are two stages in the history of a fish on the highway to decom- 

 position concerning which all will agree. First, when the odour is 

 perfectly fresh and natural, and, secondly, when the odour is putrid. In 

 the former condition the fish are fit for human food ; in the second 

 condition they should be unhesitatingly condemned. But there is an 

 intervening period between these extremes, and here it is the daily 

 experience of those engaged in the examination of fish, that it is often 

 very difficult to interpret these odours correctly as regards the indications 

 which they may give concerning the condition of a fish and its subsequent 

 fitness or unfitness for human food. It is in this intermediate stage 

 that there is room for contention and disagreement. 



Regarding this subject I have made the following observations : — 



(1) That in every case unwashed fish give off an offensive odour sooner 

 than washed fish. Hence, in smelling an unwashed fish an offensive 

 odour might be derived from decomposing slime lying on the surface, 

 although the fish itself may be quite fresh. 



(2) If fish are washed daily with sea water, or even tap water, the 

 development of an offensive odour is considerably retarded. 



(3) Ungutted fish soon develope a very disagreeable odour from the 

 decomposition which rapidly ensues, especially in the gut, and to a less 

 extent in the liver. 



(4) If fish (gutted or ungutted) in the incipient stage of decomposition, 

 and giving off a slightly-tainted odour, are thoroughly washed in sea 

 water it is remarkable how they are freshened. The tainted odour is 

 expelled and for a time they may again smell quite fresh. 



(5) Trawled fish are comparatively free from slime when taken on 

 board, because they have been dragged along for some distance through 

 the water at a considerable speed and most of the slime washed off. 

 But such fish when removed from ice soon begin to give off a tainted 

 odour, because decomposition generally sets in earlier than in line fish. 



(6) To test a fish fairly it is always necessary to find out whether the 

 smell is due to the flesh, or to the skin, or to the slime, or to all com- 

 bined. 



Regarding the odour given off as a criterion for purposes of meat 

 inspection, one has always to keep in view that the sense of smell is 

 differently developed in different individuals, and that it is impossible to 



