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Appendices to Fifth Annual Beport 



1 and the manner of its distribution ; the presence of a difficultly fusible fat 

 ' with considerable stearin would tend to hinder digestibility (as in 

 'mutton), and the same thing probably occurs when the contents of 

 ' the sarcolemma are permeated with much fat, as in the lobster and eel.' 



This is probably also the reason for Pavey 's* statement and the common 

 belief ' that fish with white flesh is less stimulating and lighter to the 

 1 stomach or more easy of digestion than fish with red flesh.' For when 

 a fish with white flesh absorbs more nutriment than it requires for its 

 immediate needs, it stores it up in its liver, and also probably in the 

 layer of red muscle along its sides, in the form of fat, whereas a fish 

 with red flesh, and more particularly the salmon, stores up its fat among 

 the fibres of its muscles, and in a distinct layer beneath its skin. In the 

 salmon this fat is more particularly stored on the abdominal side of the 

 body and hence this part has a richer flavour, and is more sought after 

 by epicures and more avoided by dyspeptics than the dorsal region. 

 Chittenden and Cummins state that their results confirm Pavey's experi- 

 ence, but the figures which they give do not bear out this statement. 

 They give as the digestibility* of the American whitefish (Coregonus 

 clupeiformis), which they believe to be similar to our whiting, 94*78, 

 that of salmon, 92 "9 2 ; but, as I have shown, this does not neces- 

 sarily prove that salmon is only a little less digestible than whiting ; 

 it only shows that from a given weight of it rather less material can be 

 dissolved that can be got from the same weight of whitefish. Probably 

 all the peptones can be extracted from the whiting in far less time than 

 they can be from the salmon. But some fish with white flesh have also a 

 greater'or smaller amount of fat incorporated with their flesh. The eel 

 above referred to by Yoit is a good example, and the mackerel, herring, 

 and sprat also contain a very considerable quantity of fat in their flesh, 

 as is shown in Table IV. These fish are well known to be less digestible 

 and more trying to a delicate stomach than such as whiting, haddock, 

 sole, turbot, or plaice. Codfish, however, is not nearly so digestible or so 

 nutritive as most other kinds of whitefish. Dr Pavey has observed several 

 cases where eating cod in a state of high perfection, that is, in a firm, flaky 

 and opaque state, after being boiled, resulted in an attack of indigestion. 

 This is doubtless partly due to the fact that cod will eat anything. When 

 they feed chiefly on Crustacea, as is generally the case with cod from the 

 Dogger Bank, they are as a rule finer flavoured and more digestible than 

 fish which have indulged in a more varied, though not so choice diet. 

 That cod is less nutritive than most other fish was shown by Chittenden 

 and Cummins; from 20 grammes of steamed cods' flesh only 2"9292 

 grammes were obtained after 22 hours digestion. This when compared 

 to beef as in other cases gives 72 '39 as the nutritive value. 



These facts will suffice to show that our knowledge of the digestibility 

 of fish is not extensive, that in fact the only definite experiments made on 

 the matter are those of Dr Beaumont above referred to. I hope before 

 the issue of the next Report, to be able to publish the result of a series of 

 experiments as to the relative time taken by our ordinary food fishes to 

 dissolve. But although no definite experiments have proved that fish is 

 more digestible than beef or mutton, that conclusion has been arrived at by 

 all who have had a wide experience in dietetics, In consequence of this, 

 fish diet is largely recommended in cases of weakness, where the stomach 

 is unable to attack such a highly nitrogenous and concentrated form of 

 nourishment as beef, and it may be that this fact has had more influence in 

 determining the popular prejudice against fish than any other. Now, 

 however, fish is being recommended in the case of people who are 



* A Treatise on Food and Dietetics, by Dr F. W, Pavey, London. 1874, p. 155. 



