PRELIMINARY OBSERVATIONS.
To most animals nature has designed a limited range of aliment, when compared to the extensive choice allotted to man. If we look into the history of the human race, inhabiting the different parts of the globe, as far as we are acquainted with it, we find, that man appears to be designed by nature to eat of all substances that are capable of nourishing him: fruits, grains, roots, herbs, flesh, fish, reptiles, and fowls, all contribute to his sustenance. He can even subsist on every variety of these substances, under every mode of preparation, dried, preserved in salt, hardened in smoke, pickled in vegetable acids, &c.
The Author of Nature has so constructed our organs of digestion, that we can accommodate ourselves to every species of aliment; no kind of food injures us; we are capable of being habituated to every species, and of converting into nutriment almost every production of nature.
When we enquire more minutely into the chemical constitution of the different alimentary materials, which promote the growth, support the strength, and renew the waste of our body, we find that animal substances are not suited to form the whole of our daily food; and that, in fact, if long and extensively used, their stimulating effects at length exhausts and debilitates the system, which it at first invigorated and supported. Those, accordingly, who have lived for any great length of time on a diet composed entirely of animal matter, become oppressed, heavy, and indolent, the tone and excitability of their frame are impaired, they are affected with indigestion, the breathing is hurried on the smallest exercise, the gums become spongy, the breath is fœtid, and the limbs swell. We recognize in this description the approach of scurvy, a disease familiar to sailors, to the inhabitants of besieged towns, and, in general, to all who are wholly deprived of a just proportion of vegetable aliment.
On the other hand, vegetable food being less stimulating is also less nourishing; besides, this kind of aliment is, upon the whole, of more difficult assimilation than the food derived from the animal kingdom. Hence it is, perhaps, that nature has provided a greater extent of digestive organs for animals wholly herbivorous. It is insufficient to raise the human system to all the strength and vigour of which it is susceptible. Flatulency of the stomach, muscular and nervous debility, and a long series of disorders, are not unfrequently the consequences of this too sparing diet. Some Eastern nations, indeed, live almost entirely on vegetable substances; but these, it is remarked, are seldom so robust, so active, or so brave, as men who live on a mixed diet of animal and vegetable food. Few, at least, in the countries of Europe can be sufficiently nourished by vegetable food alone; and even those nations, and individuals, who are said to live exclusively on vegetables, because they do not eat the flesh of animals, generally make use of milk at least, of eggs, and butter and cheese.
Food composed of animal and vegetable materials is, in truth, that which is best suited to the nature and condition of man. The proportions in which these should be used it is not easy to determine, but generally the quantity of vegetables should exceed that of animal food. “On this head,” says Dr. Fothergill, “I have only one short caution to give. Those who think it necessary to pay any attention to their health, at table, should take care that the quantity of bread, of meat, and of pudding, and of greens, should not compose, each of them, a meal, as if some only were thrown in to make weight, but carefully to observe that the sum of, altogether, do not exceed due bounds or incroach upon the first feeling of satiety.”
All the products of the vegetable kingdom, used as aliment, are not equally nutritious. When we contemplate with a chemical eye the nutritive principles contained in vegetable substances, we soon perceive that they are but few in number, namely, starch, gluten, mucilage, jelly, fixed oil, sugar, and acids; and the different vegetable parts of them are nutritious, wholesome, and digestible, according to the nature and proportion of their principles contained in them. The starch and gluten appear the most nutritious, and together with mucilage at the same time, the most abundant ingredients contained in those vegetables from which man derives his subsistence. Hence, from time immemorial, and in all parts of the earth, man has used farinaceous seeds as part of his food, for they contain the above-mentioned materials in the greatest abundance. Of these the most nutritive are the seeds of the Cerealia, under which title are commonly comprehended the Gramineæ, or Culminiferous plants. Whilst the seeds of the Gramineæ supply the most important part of food furnished by the vegetable kingdom, in almost every part of the world, their leaves and young shoots support that class of animals hence called graminivorous, whose flesh is most generally eaten.
These vegetables are distributed so universally over the face of the earth, and have become to such a degree the object of culture, that they are very generally made into bread, or are employed instead of it; and, upon the whole, it appears that they are nutritive merely in the proportion to the quantity of farinaceous matter contained in them; but this substance exists in different combinations in different cereal and leguminous seeds. It is combined with gluten in wheat, with a saccharine matter in oats, and in many leguminous seeds, such as Harricot beans and pease, and with viscous mucilage in rye and Windsor beans.
Next to the Cerealia and Leguminosæ may be ranged the oily farinaceous seeds, such as almonds, walnuts, filberts, &c. These abound in starch and mucilage. The use of chocolate, which is prepared from the chocolate nut, growing in the West Indies, ground into a paste, with or without sugar, is in itself a nutritious substance, and to those with whom it agrees, it may be considered as a wholesome nutritious aliment. Yet the vegetable farina, in this state of existence, though highly nutritious, and to many palates very agreeable, is more difficult of digestion, and does not, upon the whole, afford a very wholesome alimentary substance. When too freely used, those kinds of seeds are sure to disagree, more especially if from age the oil has become rancid. They must be considered rather as a delicacy than as fitted to form a portion of our daily food, and with some particular stomachs they never agree.
Of the alimentary farinaceous roots, the potatoe, boiled or roasted, is one of the most useful, and perhaps after the Cerealia, one of the most wholesome and most nutritious vegetables in common use; its nourishing powers, there can be no doubt, depend upon the amylaceous fecula of which it is chiefly composed. The Jerusalem artichoke deserves likewise to be noticed here, as being a highly alimentary root, chiefly composed of farinaceous matter. Of the fruits rich in farinaceous and mucilaginous matter, few are indigenous. The chesnut, when roasted, affords an alimentary food, but in the East and West Indies the bread fruit, bananas, and the fruit of the plantain tree, are the substitutes for bread.