38 Part III. — Twenty- sixth Annual Report 



critically by further tests. Also, it has to be kept in mind that, to per- 

 vent this discoloration, an attempt is sometimes made to remove the 

 large caudal vein along with the gut. 



III. The sense of smell in the examination of fish is invaluable in spite 

 of the difficulties already discussed. I have attempted to describe smell 

 in terms of fresh, fishy, and sea-weedy for one large class of fish ; as fresh, 

 fishy, and oily in another large class of fish, and to contrast these with 

 such terms in every-day use as tainted, stale, and putrid. Although one 

 at the same time recognises the different and relative degrees of develop- 

 ment of the sense of smell, and consequently the difficulty in getting 

 unanimity in different individuals of what constitutes these different 

 terms, yet the test of smell is both a time-honoured and a reliable 

 standard. One will usually find that, as the red discoloration is 

 appearing, the smell is passing from fresh to tainted and stale. The fish 

 is now on the borderland, and one smells critically for an approaching 

 putrid odour, when the fish should be at once condemned. 



IV. When a fish is fresh it requires considerable pressure to strip the flesh 

 from the backbone, and in doing so many tags of flesh are left adhering 

 to the bone. As decomposition, and consequently softening, progresses, 

 the flesh gradually strips off cleaner. Hence, when one finds that the 

 flesh comes away readily and comparatively cleanly from the bone, or 

 that the bone can be stripped readily and cleanly from the flesh, one may 

 feel convinced that the fish are certainly not fresh, that decomposition, if 

 not well advanced, has certainly commenced, and by this and other tests 

 proposed one will feel warranted in condemning such fish. 



V. In examining the interior of the abdominal cavity one notes the 

 condition of the kidney, situated anteriorly and ventral to the backbone. 

 It is a very diffuse, vascular, and friable organ, and very rapidly breaks 

 down, passing through different shades of colour, to form a reddish-brown 

 debris in from 24 to 48 hours, while the fish may be still quite fresh. 

 But more important is the condition of the abdominal walls. If they are 

 firm and elastic, with absence of discoloration and presence of fresh, 

 characteristic smell, one may feel assured that the fish are fresh. On the 

 other hand, if the walls are soft and pulpy, with apple- jelly-like appear- 

 ance and presence of discoloration, with tainted odour, while the fish is 

 becoming alkaline to litmus paper, then such fish require very careful 

 consideration, and it will generally be found that, with other confirmatory 

 evidence present, such fish should be condemned. 



Other common tests which should never be omitted are — 



VI. The Appearance of the Gills. — The gills of most fish are red in 

 colour, with certain specific tints. These tints disappear in about from 

 24 to 36 hours, and the gills become grey and slimy by the third to 

 fourth day. So long as the gills retain their natural colour there is a 

 strong presumption that the fish are fresh. But one has to keep in view 

 that the gills often retain their characteristic colour with little change — 

 especially if washed daily in tap or, still more, sea water — even when the 

 flesh is becoming putrid ; that on the whole the gills of trawled fish are 

 often paler at the time of capture than line fish, and more so the longer 

 they have been in the trawl net ; also that one finds degrees of paleness 

 even among perfectly fresh fish. 



VII. The Appearance oj the Eye. — The appearance of the eye should 

 always be noted. The full and prominent eye, with jet-black pupil and 

 transparent cornea, of the fresh fish presents a very decided contrast to the 

 grey and shrunken eye of a fish four or five days after capture. 



VIII. The Appearance of the Scales. — One notes the absence or presence 

 of characteristic sheen, the firmness or looseness of the scales, and if they 



