158 ECONOMY OF HUMAN DIET. 
Those articles of food in which the nitrogenous compounds — 
predominate, are especially fitted for the maintenance of the — 
solid fabric of the body ; whilst those in which the carbon- 
aceous compounds are in largest excess, are those which are 
most effective as supplying materials for the combustive pro- 
cess. Conspicuous among the former are the various kinds 
of animal flesh, as also the white of eggs ; whilst among the 
latter the most noticeable are bacon and butter, rice and 
potatoes, the former consisting almost wholly of fat, the latter 
being chiefly composed of starch. Of all single articles of 
food, good wheaten bread, in which the proportion of nitro- 
genous to carbonaceous components is about as 5.7 to I, 
seems to be the one best suited to the ordinary wants of 
Man ; but this acquires much additional value from the con-. 
current use of a moderate amount of fatty matter in the form 
of butter. 
165. If the more highly azotized forms of food be em- 
ployed exclusively, a great excess of them must be consumed 
to supply the carbon needed for respiration ; whilst if the 
more carbonaceous kinds of food be used as the sole susten- 
ance, unless the quantity ingested be large enough to afford 
the requisite supply of azotized material for the maintenance 
of the tissues, their nutrition must be imperfectly effected, 
and the strength must fail. Not only in the instance just 
cited, but in a variety of others, the instincts of mankind 
have led to such a combination of different articles of diet, 
as includes in their appropriate proportions the albuminous, 
the saccharine, and the oleaginous principles. Thus with 
meat we eat potatoes ; and with the white meats which are 
deficient in fat, we eat bacon. "We use melted butter with 
most kinds of fish, or fry them in oil ; whilst the herring, the 
salmon, and the eel, are usually fat enough in themselves, and 
are dressed and eaten alone. A similar adjustment is made 
when we mix eggs and butter with sago, tapioca, and rice ; 
when we add oil and the yolk of an egg to salad ; when we 
boil rice with milk, and combine cheese with maccaroni. 
Bacon and greens, and pork and pease-pudding, again, are 
combinations founded in taste, which approve themselves to 
the judgment; as is also the Irish dish termed kolcannon, con- 
sisting of potatoes and cabbage, with a little bacon or fat pork.: 
So are the mixture so common in Ireland and Alsace, of butter- 
