Diseases of meat present peculiar appearances, sometimes easily recognisable, at others not so obvious. One of the most deadly of these is the presence of encysted parasites known in pork by the scientific name of trichina spiralis. The dangers incident to the presence of this deadly parasite are only to be overcome by a full cooking temperature equal to that of boiling water. There are various other diseases of animals which render their flesh unsuitable for human food. But the length of time during which meat may be kept short of the production of real putrefaction has yet to be determined as bearing upon its wholesomeness. This is a point to which we have directed attention, and we hope at no distant date to be assured that its dietetic importance is more generally appreciated.

FISH.

The flesh of fish bears a closer resemblance to butchers' meat than is sometimes recognised. Indeed, the analogy between the flesh of sturgeon and veal is sufficiently obvious both in appearance and flavour. The difference between certain kinds of fish having what is termed white flesh and other fish having red or pink flesh will not always afford any indication as to the relative proportion of nutriment which either kind may possess in nitro

genous substance, soluble albuminoid matter, and even less in regard to its constituent of oil. But it may be accepted that those fish which contain the largest quantity of oil are, from that very fact, more liable to prove difficult of digestion.

The fibrinous portion of many descriptions of fish is naturally harder and coarser than the generality of animal flesh. The necessity is, therefore, greater that in cooking every attention should be given to rendering the muscular fibre as tender as possible.

In consequence of some little delicacy being requisite in the preparation of fish for the table, no little prejudice has been excited against it among the labouring classes. It is also supposed to be very inferior to flesh meat in nutriment. This is not the case to the extent supposed, the amount of nitrogenous matter being, on an average, about the same as in lean meat; it is, however, generally less available, as it cannot be kept fresh for the same length of time. Notwithstanding which, if difficulties had not been interposed by those interested in Billingsgate Market, a very large quantity of most valuable food might be daily brought to London, and retailed at the most moderate prices.*

* The establishment of wholesale and retail markets for fish in London has been again and again attempted, and the history of Columbia Market affords one of the most lamentable instances of failure.

All efforts to accomplish this have unfortunately up to the present time been frustrated by trade devices, and while thousands throughout the country are suffering in health from the want of that description of nourishment which fish would cheaply afford, thousands of tons of fish are permitted to rot as manure on the sea coast.

CHAPTER V.

VEGETABLES AND FRUIT.

VEGETABLES must be dealt with, for our pre

sent purpose of illustration, from a totally different point of view from that in which the botanist, herbalist, or vegetarian would regard them. Wehave no intention of treating of the vegetable kingdom in general, much less of attempting to give any idea of the food principles peculiar to any very extended series of edible vegetable matters. Some of the commonest of those vegetables which find their way to our tables will be quite sufficient to enable us to point out the leading features which must be thoroughly recognised as appertaining more particularly to this very varied and important group of food substances.

If, for one reason more than another, we should select, even if we were not compelled, a few of the commoner descriptions of vegetables as types, it would be because that vast variety which does exist of vegetable productions suitable for the table is unfortunately almost unattainable in this country. Potatoes, cabbages, onions, carrots, and turnips,

with a few more, express the extreme limits of all that an ordinary greengrocer desires to offer his customers for selection; the rest are luxuries, and must be paid for as such, even if, as is the case with some of the choicest of our salads, they can be obtained by those who seek them at the mere cost of collection.

The potato may, perhaps, be taken as the most generally valuable of our common table vegetables. The natural assumption of food value accorded to the potato depends not only upon its solidity (containing a quarter its weight of solid matters, the remaining three quarters being water), but also from the circumstance that these solids contain no less than 16 or 17 per cent. of starch, and from 1 to 2 per cent. nitrogenous matter, together with mineral matters of a very varied constitution.

The estimate of the nutrition which this vegetable affords is not entirely to be confined to the properties of its components, but also to the existence of certain dilute acids, citric and phosphoric, which probably cause a remarkable anti-scorbutic effect to be produced by the raw potato. How much of this citric and phosphoric acid is preserved after the process of cooking must depend considerably upon the method adopted. But the hygienic value of potatoes which have neither ger