« PreviousContinue »
willing to regard these declarations of his diffidence as virtual engagements to render his work more worthy of the public attention, if another edition shall be called for; and this, we think, he cannot more effectually accomplish than by a judicious contraction of its dimensions.
We shall be careful to announce the remaining volumes, as soon as they make their appearance.
ART. II.-History of the Progress and present State of Animal Chemistry. By W. B. Johnson, M. B. 3 vols. 8vo. 11. 43. Johnson. 1804.
CURIOSITY has stimulated experimental philosophers to investigate the nature, properties, and constituent parts, of almost every inanimate substance: metaphysicians have treated copiously on the nature and powers of the human mind: anatomists have accurately developed the mechanism of animals: but there seems to be a natural repugnance to explore the component principles of animalized bodies. Any attempt, therefore, to collect the scattered opinions and isolated experiments of the philosophic investigators of animal substances, must be hailed alike by the speculative chemist and the physiologist, as a work calculated to be of primary utility. To the former it should present a mirror in which the imperfections and deficiencies of his science are displayed: to the latter, suggest new analogies, new combinations of medicines to augment their curative powers, and facilitate the progress of the healing art. From the experimentalist, whose mind, ever intent on new discoveries, is devoted to the accurate observation and examination of all the numerous appearances, affinities, and new results, of his operations, little critical arrangement is to be expected. It is the business of the historian, unoccupied by original inquiries, to combine, arrange in chronological order, and collect into a small but powerful focus, detached facts and explanatory opinions, in order to present a complete view of the origin, progress, and actual state, of any science. But what shall we say to the mere historian, who, totally regardless of dates and the natural progress of knowledge, presents us with an irregular mass of incoherent experiments and opinions, translated or transcribed with all that verbosity which an over-anxiety to be perspicuous often erroneously adopts? A protracted history of experiments, in a monotonous style so much more tedious than that of the originals, that it conveys no idea of the idiosyncracy or point in view of the different operators, replete with unimportant repetitions (pages 19, 21, &c.), without any attention to eras, to philological accuracy, and still less to the relative
quantities of the results of chemical analysisSuch, we fear, will be found the present work.
The author, after referring to the system of Dauberton,—a work too modern to be original, and too old to contain the late discoveries, proceeds to divide the animal substances that have been submitted to any chemical analysis, in the following manner: 1. Fluids: 2. Solids: 3. Hard Parts: 4. External Parts: 5. Oils: 6. Acids: 7. Poisons: 8. Aromatics: 9. Colouring Matter: 10. Concretions: and 11. Excrements.' (P. 2.) A recapitulation of the component parts of animal bodies; and an ap pendix of oviparous quadrupeds, insects, &c. terminate the second volume: and the third is on life-irritability, respiration and animal heat-death-putrefaction.'
The division is at once extremely inaccurate, redundant, and incomplete. The terms solids' and 'hard parts' may serve for the purposes of surgery, but are too inaccurate to be tolerated in the modern language of chemistry, Animal 'oils' rarely or never exist naturally in the fluid state, and therefore might have been treated as 'solids.' 'Aromatics,' under which indefinite term we find only ambergris, castor, civet, and musk, are so nearly allied to animal 'concretions,' that it will only perplex the memory and propagate false notions, to treat them under distinct heads. Almost every animal substance has its peculiar aroma, or odoriferous principle; but on that account must not be placed in a distinct division.-Nor do we find more accuracy or perspicuity in the subordinate arrangements. The author presents us, throughout the work, with a crude collection of experiments which are presumed to be the actual state of our knowledge, then subjoins a general recapitulation: thus reversing the order of his title, and the natural progress of human science. . Dr. Johnson, after slightly mentioning the different methods of analysing animal substances, commences with experiments on eggs, which Fourcroy supposes to be coagulated by the magic powers of oxigen. Carradori, however, more correctly shews that oxigen is not even absorbed by the white of eggs; the volume of which is not changed either in the coagulated or liquid He attributes coagulation to a change produced by the solvent power of caloric, and the disposition of the integrant parts of the white to obey the force of cohesion.
By analysis the blood is divided into three parts :-Ist, The white serum (which contains albumen and gelatin): 2d, The red serum, or colouring matter: and 3d, The fibrin. The white serum is more abundant than the fibrin, and the red the least.' Its component parts consist of oxigen, azote, hydrogen, carbon, sulphur, phosphoric acid, soda, lime, iron, and a peculiar aroma. To these we might add caloric; and, however they may be actually component parts according to the nature
and variety of our food, it is yet extremely improbable that they are all essential or constituent parts of the vital fluid. On this head we know enough of the character of Fourcroy, to regard his avowedly imperfect experiments on the blood of the foetus, as a jeu d'esprit. The membranous matter, or fibrin, of the blood, is separable by rubbing the coagulum between the fingers in water; which carries away the colouring matter, and leaves the real fibrin, that has sometimes been confounded with the coagulable lymph. According to physiologists, fibrin is destined for the purpose of forming and repairing the substance of the muscles. Our author details the causes of the coagulation of the blood (allowing it a vital principle), after the French chemists Parmentier and Deyeux; whose speculations contain nothing which cannot be traced to those of Hunter, Hewson, &c. Dr Johnson seems not to have known the experiments on muscular irritability with the galvanic fluid.
The examination of milk, and its acetous and vinous fermentations, shews, according to Stipriaan, that the greatest quantity of spirit is obtained from the milk of the cow; while Plenek affirms that of the mare, as containing the greater abundance of sugar. The remote component parts of milk are oxigen, hydrogen, carbon, soda, azote, phosphorus, and lime, and some chemists add iron. Then follows (admirable arrangement!) a history of milk,' with more desultory experiments, and a pompous account of the peculiar excellence of the Roquefort cheese, made of sheep's and ass's milk. As the author has never tasted it at Roquefort, we can assure him from experience that even there, if he has the palate of an Englishman, he would esteem it very inferior, both in flavour and texture, to the common cheese in Wales.
On the gastric juice, or menstruum in the stomach that facilitates digestion, the experiments of the Italian chemists Carminati, Brugnatelli, and Scopoli, particularly the latter, drawn from French accounts, are very incorrectly related. This fluid, taken from the human body in health, is composed of water neither acid nor alkaline, muriat of soda, and an animal substance said to afford phosphat of ammonia. We subjoin the following extract; which, if not useful against the prevalent disease of empiricism, may perhaps amuse some of our sedentary readers who are troubled with indigestions, &c.
• Substances insoluble, or that were not digested in the usual time (three hours) in the stomach, according to Gosse of Geneva.
Animal substances:-1. Tendinous parts: 2. Bones: 3. Oily or fatty parts: 4. Indurated white of egg egg. Vegetable substances;
*This is not to be understood of fat meat. REV.
1. Oily or emulsive seeds: 2. Expressed oils of different nuts and kernels: 3. Dried grapes, and the skins of fish: 4. Rind of farinaceous substances: 5. Pods of beans and pease: 6. Skins of stone fruits: 7. Husks of fruits with grains or seeds: 8. Capsules of fruit with grains: 9. Ligneous stones of fruits, &c.
"Substances partly soluble, or parts of which were digested.
Animal substances:-1. Pork dressed various ways: 2. Black puddings: 3. Fritters of eggs, fried eggs and bacon. Vegetable substances:-1. Sallads of different kinds, rendered more so when dressed: 2. White cabbage less soluble than red: 3. Beet, cardoons, onions, and leeks: 4. Roots of scurvy grass, red and yellow Carrots, succory, are more insoluble in the form of sallad than any other way: 5. The pulp of fruit with seeds, when not fluid: 6. Warm bread and sweet pastry, from their producing acidity: 7. Fresh and dry figs. By frying all the substances in butter or oil they became still less soluble (digestible). If not dissolved in the stomach, they are, however, in their passage through the intestines. Substances soluble or easy of digestion, and which are reduced to a pulp in an hour and half.
Animal substances:-1. Veal, lamb, all gelatinous substances, and in general the flesh of young animals, are sooner dissolved than that of old: 2. Fresh eggs: 3. Cow's milk: 4. Perch boiled with a little salt and parsley: when fried or seasoned with oil, wine, and white sauce, it is not so soluble. Vegetable substances:-1. Herbs, as spinach mixed with sorrel, are less soluble. Celery, tops of asparagus, and hops: 2. Bottom of artichokes: 3. Boiled pulp of fruits, seasoned with sugar: 4. Pulp or meal of farinaceous seeds: 5. Different sorts of wheaten bread, without butter, the second day after baking, the crust more so than the crumb. Salted bread more so than that without salt; brown bread in proportion as it contains more bran is less soluble: 6. Rapes, turnips, potatoes, parsnips, not too old.
Substances which facilitated the menstrual power of the gastric juice, are sea salt, spices, mustard, scurvy-grass, horse-radish, radish, capers, wine, spirits in small quantities, cheese, particularly when old, sugar, various bitters.
Substances which retarded the gastric power, are water, particularly hot, all acids, astringents, Peruvian bark taken after dinner : unctuous substances, kermes, corrosive sublimate, &c. Gosse likewise observed, that employment after a meal suspended or retarded digestion, as well as leaning with the breast against a table, and that repose of mind, vertical position and gentle exercise facilitated it." Vol. I. P. 210.
It appears that Carminati, by digesting two drachms of fresh veal in an ounce of spring water, adding five grains of common salt, exposing it to the heat of about 100° of Fahrenheit for sixteen hours, and decanting the liquor, imitated the gastric juice of carnivorous animals. By repeated digestion with fresh flesh, he found it became much stronger, and more similar to the natural gastric juice. Struve, with phosphoric acid and CRIT. REV. Vol. 4. April, 1805.
volatile alkali, made a liquor which produced an effect similar to the gastric juice on aliments.
The bile, considered as a necessary stimulus to the intestines, keeping up their energy and peristaltic motion, and thereby facilitating digestion, according to Dr. Saunders, contains: 1. Water impregnated with the odorous principle: 2. A mucilaginous substance, resembling the albumen: 3. A resinous substance containing the colouring principle and bitter taste: and 4. The mild mineral alkali. The combination of the bitter resin with the alkali, he supposes, forms the saponaceous matter. Fourcroy calls it a biliary or real animal soap. Our author here offers his own opinion, and considers it, with Galen and Paracelsus, merely an excrement.
< If I may be permitted to hazard a conjecture upon the use of the bile, and the viscus that secretes it, it would appear, as Fourcroy has well observed, that the liver has a great connection with the Jungs, not only from the facts already mentioned, but from the large size of this viscus in the foetus which has not yet respired; and that whatever action the bile may have upon the food, or on the intestines in digestion, there is reason to believe that the liver deprives the blood which passes through it of some of its noxious parts, performing an excrementitious operation in the abdomen, whilst the lungs are acting to the same end in the thorax. This appears probable, not only from the large size of the liver in those animals of limited respiration, but even the extent of this viscus in man and quadrupeds, which is by far the most voluminous gland in the body, indicates, that its action must be of greater extent than that of furnishing a mere secretion. All the glands form their secretions from the blood in its most perfect state, or as it circulates through the arteries; whilst, on the contrary, the liver makes use of the inpure venous blood, supplied by the vena porta; which blood has been said by some, although denied by others, to be in a state of greater fluidity, and to have a putrescent tendency, so as scarcely or not at all to be coagulated; or in other words, possessing a superabundance of soda, which preserves its fluidity, and of carbon and hydrogen, which give it a dark colour. If this be the case, it is probable, that as this blood circulates through the liver, this viscus deprives it of hydrogen and carbon, which, united to a little oxygen, form an oily matter, and meeting with the soda, a saponaceous substance is produced, which forms the principal character of the bile. Hence arises the necessity of this fluid being made with constancy and regularity, for the integrity of all the functions; and the reason of its existing in all animals, and of its being as necessary as the evacuation of the lungs during respiration. In those animals whose respiratory organs are very small in comparison to their body, and where the carbon and hydrogen must be in large quantity in their blood from the want of proper evacuation, the liver is remarkably capacious and great in proportion, by which means these substances are evacuated in the form of bile, the act of respiration being incon