II 



bearing of which on the subject of a fish dietary will 

 appear. 



. The first is the effect of hard labour involving consider- 

 able muscular exertion. 



The second is the influence of climate or of temperature 

 on the body. 



The third is the influence of age. 



In relation to the effect of continued muscular exertion, 

 it must be manifest that the porter, the navvy, the labour- 

 ing mechanic, the agricultural labourer, and the marching 

 soldier, require food in quantity and kind, differing widely 

 from that which the sedentary man of letters and the 

 counting-house clerk demand ; marked and contrasted 

 types which we may refer to hereafter, and between which 

 innumerable modifications of condition exist. 



For the purpose of sustaining severe and continued 

 muscular exercise, the diet must contain a good proportion 

 of fatty matters, and of starchy matters ; also a moderate 

 amount of albuminoid or flesh-forming elements, together 

 with earthy and other salts of course. All but one of 

 these are present in the flesh of animals, the missing 

 element, starch, being supplied by adding bread, potatoes, 

 rice, &c., a practice which has been empirically followed 

 for ages, long before the physiological reason was known. 

 Many cereal grains, wheat, oats, &c., and also peas and 

 beans, contain both flesh-forming material and starch ; 

 hence bread has been termed, not quite correctly, but 

 nearly so, the " staff of life." All these are deficient in 

 fatty matters, which are necessary to the working-man, 

 who adds butter, bacon, suet, lard, or oil (in other countries), 

 in order to supply his expenditure. No hard labour can 

 be achieved without the consumption of a considerable 

 amount of fatty substance. For our labourers then, all 



