DR. PEREIRA'S TREATISE ON FOOD AND DIET.

BESIDES his lectures, Dr. PEREIRA is well known for his able and elaborate work on the Materia Medics; of which the present publication is a species of continuation. In the former book, Dr. PEREIRA gave a systematic account of physic, as in the present he treats of food: and, apart from the general interest of the subject, and the great number of facts the volume contains, its distinguish- ing characteristic will be found to consist in its condensed account of nutritive substances, embracing the result of the labours of modern chemists tested by the author's own experience. The Treatise on Food and Diet consists of two main parts, each extensively subdivided. The leading subject of the first part is food in its own nature ; whilst in the second part its applica- tion to our use is considered. In treating of food generally, Dr. Pesetas first examines its chemical elements, or those elements into which all nutritive matters may be finally resolved—as carbon, hydrogen: he next considers simple aliments, which are formed by the combination of two or more of the primary elements—such as water, sugar : after which, he proceeds to compound aliments that arise from a combination of the simple. The analysis of different kinds of food is next exhibited; and their nutritive powers, with their other effects upon the system, are described both from "a priori deduction and experience. And this section forms the largest part of the volume; embracing every article swallowed by civilized man, liquid as well as solid; extending from water to eau de vie, and from corn and milk to beef, venison, poultry, and fish. The second part is less minute and more general than the first, though its principle of arrangement is similar. After briefly expounding the nature of digestion, and the manner in which digested food is prepared for conversion into our own substance, Dr. PEREIRA points out the varying nature of the digestibility of food ; either from circumstances appertaining to the food itself—as its toughness, tenderness, mode of cookery ; or from the condition of the individual taking it—as peculiarities of constitution, fatigue at the time of eating, and so forth. He then enters into a short resume of the nutritive qualities of different kinds of food; offers some hints as to the times of eating; and gives an exposition of the dietetical regimen suited to a disordered state of the digestive organs. Embraced in this section, though perhaps scarcely belong- ing to it, is a tabular exhibition of the dietaries allowed by the Poor-law Commissioners to paupers, and by the Home Office to prisoners, together with those of the different London Hospitals, and some other public institutions; Dr. PEREIRA interspersing critical remarks on this agitated question, from which it appears that he does not consider any of them too high, though some of them may be sufficient. From this account it may be inferred that the character of the volume is rather s,:ientific than popular : and such it undoubtedly is, but more in plan than in treatment. Every thing is perfectly clear, so far as it can be made so. The leading data are dis- tinctly presented at the outset, and all that follows has a reference to the preliminaries : but the results of scientific analysis, ex- hibited in technical forms, of necessity require some knowledge and much attention to understand. Without one, or indeed both, the chemical principles on which food itself depends, and to which its respective nutritive powers are owing, can no more be com- prehended than a quotation in an unknown tongue. These re- marks, however, apply only to a small portion of the book—to a part of the introduction, and to the account of the composition of each article, when first brought before the reader. The general disquisitions, and the examination of each kind of food, are not only intelligible but popular, as well in matter as in manner. Take a faw examples.

WHAT BECOMES OF ALCOHOL ?

Alcohol is classed among the elements of respiration ; and it =meet be doubted that it undergoes some change in the animal economy. When taken into the stomach,it is absorbed, and gets into the circulating mass. Now, how does it get out of the system ? Certainly not by the bowels, urine, or akin. A portion of it escapes by the lungs, and is recognizable by its odour in the breath; but the quantity in this way thrown out of the system is comparatively small, and is certainly quite disproportionate to that often swallowed. More- over, it is principally when the quantity taken is very large that it is most re- cognizable in the breath ; when, in fact, the function of respiration is very im- perfectly performed. What, then, becomes of it ? By itself it cannot form tissues, since it is deficient in some of their essential ingredients, namely, nitrogen, sulphur, and phosphorus; and there is no reason to suppose that it contributes, even in part, to the renovation of tissues. Liebig's suggestion, that it is burnt in the lungs, and thereby converted into carbonic acid and water, appears to me a very plausible one. Now, to convert it into these sub- stances, it merely requires oxygen.

Conversion of Alcohol into Carbonic Acid and Water.

Alcohol C4 .116 0 I Carbonic Acid C4 — 03 Oxygen — — 0" I Water — II6 06

Total C4 He 014 Total 04 Hs 014 By its oxidation in the lungs it must evolve caloric ; and thus, when used in moderation, it serves to support the temperature of the body. This use of it in the animal system appears to have been quite overlooked by the Temperance and Tea-total Societies.

Alcohol, therefore, is a fuel in the animal economy, by the combustion of which caloric is evolved. Common experience favours this view. Coachmen and others take it in cold weather to keep them warm, and it is familiarly used to prevent what is commonly called "catching cold." In cases of ex- treme suffering and exhaustion from excessive exertion and privation of food, the cautions and moderate dietetical use of spirit has on many occasions proved invaluable. In Captain Bligh's account of the sufferings of himself and companions in consequence of the mutiny of the crew of the Bounty, he observes, "The little rum we had was of great service : when our nights were particularly distressing, I generally served a tea-spoonful or two to each person ; and it was joyful tidings when they heard of my intentions." It is said that the inhabitants of colder climates 'take more spirit than others, and with less injury. Liebig accounts for this by saying that they inhale a more condensed air—that is, they take in more oxygen at every inspiration : combustion is more rapid in them, and thus the elements of the alcohol are more speedily got rid of.

I trust that in offering these remarks on the effects of alcohol I may not be misunderstood. I do not wish to cast any reflections on the societies before referred to; whose motives I highly esteem, and whose objects I would gladly promote. Though alcohol evolves heat in burning, it is an obnoxious fuel. Its volatility, and the facility with which it permeates membranes and tissues, enable it to be rapidly absorbed; and when it gets into the blood it exerts a most injurious operation, before it is burnt in the lungs, on the brain and the liver. Though by its combustion heat is evolved, yet, under ordinary cir- cumstances, there are other better, safer, and less injurious combustibles to be burned in the vital lamp.

Although Dr. PEREIRA approves of the Temperance Societies, we infer that he has not yet taken "the pledge." There is more

zest than the spirit of Teetotalism would produce in this ac- count of

ARRACK OR RACK.

This is a spirit obtained from different sources in various parts of the East. In Batavia it is procured by distillation from fermented infusions of rice ; whence it has been termed rice spirit. In Ceylon, it is obtained by distillation from fermented cocoa-nut toddy (by some called palm wine.): Pine-apples steeped in it impart a most exquisite flavour to the spirit ; and by age it be- comes a delicious liqueur, which is unrivalled in the world for making motorist punch. Arrack is said to be distinguished from the other ardent spirits by its stimulating and narcotic properties. It is sometimes used in this country. to impart an agreeable flavour to punch. A mock arrack is made by dissolving twenty grains of benzoic acid in two pints of ram.

Our author's research has not been confined to the library or laboratory, or his practice to the symposium. He has penetrated the arcana of the kitchen, and made interest with cooks to be initiated into their mysteries.

HOW TO DRESS WHITE BAIT.

Having had an opportunity of seeing the mode of cooking the fish as prac- tised at Lovegrove's at Blackwell, the following notice of tilt process may not, perhaps, be uninteresting.

I was informed that the fish should be cooked within an hour after being caught, or they are apt to cling together. Those which I saw cooked were contained in water in a pan, from which they were from time to time re- moved, as required, by a skimmer. They were then thrown on a stratum of flour contained in a large napkin, in which they were shaken until completely enveloped in flour. In this state they were placed in a cullender, and all the superfluous flour removed by sifting. They were now thrown into hot melted lard, contained in a copper cauldron or stew-vessel placed over a charcoal fire. A kind of ebullition immediately commenced, and in about two minutes they were removed by a tin skimmer, thrown into a cullender to drain, and served up by placing them on a fish-drainer in a dish. At table they are flavoured with cayenne and lemon-juice, and eaten with brown-bread and batter; iced punch being the favourite accompanying beverage.

DANGEROUS FREEDOM OF INDUSTRY.

The volatile oil of bitter almonds (frequently sold in the shops as essence of bitter almonds) is a most potent poison, being in general four times as pow- erful as the prussic acid kept in chemists' shops. A single drop of it will kill a cat in a few minutes. Sir Benjamin Brodie happening to touch his tongue with a probe which had been dipped in it, suffered, almost instantaneously, an indescribable sensation at the pit of the stomach, feebleness of the limbs, and loss of power over the muscles. These effects were, however, quite transient. A few years ago, a lady in Aldersgate Street, London, was accidentally killed by it. She sent to a chemist's shop for beech-nut oil, to destroy worms ; and the person in the shop, mistaking the inquiry for peach-nut oil, served her with oil of bitter almonds, of which she took half an ounce; by which she lost her life. An hypochondriacal gentleman, forty-eight years old, swallowed about two teaspoonfuls of the oil ; and in a few minutes after was found by his servant, lying in bed, with his features spasmodically contracted, his eyes fixed, staring, and turned upwards, and his chest heaving convulsively and hurriedly. A. physician, who entered the room twenty minutes after the draught had been taken, found him quite insensible, the pupils immoveable, the breathing ster- torous and slow, the pulse feeble' and only thirty in a minute, and the breath exhaling strongly the odour of bitter almonds. Death ensued ten minutes afterwards. With these facts before us, it is, I conceive, highly improper for ignorant persons to employ it : yet it is extensively used by cooks and Con- fectioners, for flavouring.

STAFF OP LIFE.

Notwithstanding that bread is denominated the staff Of life, alone it does not appear to be capable of supporting prolonged human existence. Boussingantt came to this conclusion from observing the small quantity of nitrogen who* it contains; and the Reports of the Inspectors of Prisons on the effects of -diet of Incsinat water favour this notion..

MILE.

Good milk is quite liquid and homogeneous, not viscid; and when examined by the microscope, is found to contain only spherical transparent globules, so- luble in alkalies and ether. Moreover, pod milk yields a flocculent precipitate with acetic acid, but is not coagulated by beat. The relative quantity of cream which it affords is estimated by a glass tube divided into one hundred parts. Such an instrument is called a lactometer. The thickness of the layer of cream which, in a few hours, forms at the top of the milk, may be easily read off. I have repeatedly submitted the milk supplied to me by a respectable dealer in this metropolis to examination by the lactometer; but the results have been very unsatisfactory, as the quantity of cream which I procured varied from 5

to 23 per cent by measure. • The milk yielded by an Alderney cow, belonging to a gentleman in the neighbourhood of Whitechapel, yielded 17.i per cent (by measure) of cream.

NURSERY HINT.

The natural appetite I believe to he an index of the wants of the system, and ought therefore to be consulted, to a certain extent, in the dieting of children ; and I believe that parents commit a gross error who totally disregard it. I have seen children refused vegetable food, though they ardently desired it, be- cause they would not eat what their nurses supposed to he the proper propor- tion of animal food ; and, on the other hand, I have known children denied animal food, on the mistaken notion that it would be injurious to them, though the digestive functions were active and the appetite fur meat most keen.

In a popular sense there will be one unsatisfactory feeling about the volume, which in a scientific point of view is perhaps a met-it. The dyspeptic will find no regular system of diet laid down for him ; no minute prescription of what he should take for breakfast, dinner, tea, and supper, with directions as to how he should take it and comport himseliafterwards. But the fact is, such rules are matters of individual application. A strong constitution, with a healthy digestion and using vigorous exercise, may eat almost any thing with impunity, unless the person has some idiosyncracy, which experience alone can find out. On the other hand, almost any thing will or may disagree with a delicate person whose digestion is very much impaired. "What modes of food betwixt each wide extreme!" is a matter for particular professional direction, assisted by the experience of the patieut.