Part 147
Clysters usually consist of some weak glutinous or mucilaginous fluid, to which the active ingredients are added; or a decoction or infusion is made of the medicaments, which is then used, either alone, or after the addition of a little gum, starch, or sugar. The proper vehicle for astringent vegetable matter, metallic salts, and the mineral acids, is pure water. Oleaginous and resinous substances are made into emulsions before being employed for enemas. In all cases the fluid is administered warm. The quantity of fluid forming a clyster, for an adult, may vary from 1/2 to 3/4 pint; that for an infant within a month old, should be about 1 fl. oz.; for a child of one year, about 2-1/2 fl. oz.; from one to seven years, from 3 or 4 fl. oz.; and from seven to twelve or fourteen, 6 or 7 fl. oz.; after that age to puberty, 1/2 pint may be employed.
The quantity or dose of the active ingredients in a clyster should be 4 or 5 times as great as that of the same medicines when taken by the mouth; as it is generally regarded that the susceptibility of the rectum is only 1/5th that of the stomach, and that to exert a like absorbent action it occupies 5 times as long as the latter viscus. The dose, and the interval between its repetition, should, therefore, be proportionately increased. Narcotics, as opium, tobacco, &c., should, however, be given in only twice or thrice the quantity that would be exhibited in the usual manner.
Enemata are usually administered by means of a syringe, bladder, or elastic bag, furnished with a rectum tube; but many ingenious and elegant pieces of mechanism, adapted for self-administration, are made by the instrument makers. Great care should be taken to avoid injuring the coats of the rectum by the use of a rough or improperly shaped pipe, or one that is too long. The extremity of the pipe or tube should also be perfectly smooth and well rounded (rather spherical than pointed), and in using it no force should be employed. A neglect of this point often produces very serious consequences, especially in young children.
Tobacco smoke may be administered by means of a double pair of bellows, supplied with air from a small funnel under which the herb is burning,--and gaseous matter, by connecting the rectum tube with a small gasometer, exerting a trifling pressure on the confined gas.
The number of substances employed in the preparation of enemata is very great. The following are some of them, arranged according to their effects:--
1. (Anodyne and Narcotic.) Opium, henbane, &c., are employed to allay spasms of the bowels, stomach, uterus, bladder, &c.
2. (Aperient or Cathartic.) Aloes, colocynth, senna, various purging salts, gruel, decoction of marshmallows, decoction of linseed, warm water, &c., are commonly employed to promote the peristaltic action of the bowels, or to destroy worms.
3. (Demulcent and Emollient.) Decoction of starch, gum, isinglass, glue, &c., either alone or combined with opium, are used to protect the coats of the intestines, and to allay irritation; and also to restrain diarrh[oe]a, especially when combined with astringents, as logwood, catechu, or oak bark.
4. (Nutrient.) Animal jelly, soups, broths, milks, &c., are frequently used as injections to convey nourishment to the body.
5. (Sedative.) Tobacco infusion or smoke, and tartar emetic (in solution), are employed to relax the powers of the body, to remove spasms, depress the circulation, and to produce syncope.
Enemata or clysters are now very frequently employed in our large towns, especially among the higher classes; but a great prejudice exists among many persons against their use, arising from a fastidious and mistaken delicacy. The introduction of improved apparatus of late years, by which the administration of these remedies is attended with less difficulty and exposure than formerly, has removed much of the repugnance which previously existed.
Clysters are invaluable when it is necessary to evacuate the bowels as speedily as possible, and when the stomach will not bear the administration of a purgative by the mouth, as well as in cases requiring a direct medication of the lower bowels, as in dysentery, colic, &c. As a mere laxative, an injection of tepid water, milk-and-water, or water gruel, will generally be found sufficient. By the addition of 1 or 2 table-spoonfuls of common salt, Epsom salts, salad oil, or molasses, to this laxative enema, it will form an excellent purgative one, which will, in most cases, induce a full discharge. In all cases, the patient should be directed to retain the injection for as long a time as possible, and not to attempt to empty his bowels immediately after the reception of the medicine. "In irritation of the bladder, rectum, or uterus, an anodyne injection or enema often affords much relief. In diseases of the lower bowels, clysters are also of almost indispensable utility, as also in the dislodgment of ascarides seated in the rectum; nor are they less beneficial in those cases of sudden sinking of the powers of life where deglutition is impossible, and yet a prompt stimulating impression is requisite to save the patient; under such circumstances, clysters of some of the diffusible stimuli have proved of the greatest benefit."
The injection of large quantities of liquid matter into the bowels, as well as the constant use of clysters (even of warm water only), is deemed by the highest medical authorities to be injurious, and occasionally dangerous. The practice should not, therefore, be allowed to grow into a habit. The bowels continually accustomed to a stimulant cease to act without one. The same remarks apply to aperients taken by the mouth.
The following formulæ embrace the whole of the enemas (ENEMATA) of the 'British Pharmacop[oe]ia,' as well as a few others in common use:--
=Enema of Albu'men.= _Syn._ ENEMA ALBUMINIS, L. _Prep._ (Ricord) Infusion of linseed, 12 oz.; whites of 2 or 3 eggs; mix. In chronic diarrh[oe]a, and as a nutritient clyster in debility from stomach diseases. The reason for rejecting the yolks of the eggs is not very obvious, as the preparation is much more effective with them.
=Enema of Al'oes.= _Syn._ ENEMA ALOËS (B. P.), L. _Prep._ From aloes, 2 scrup.; carbonate of potassa, 15 gr.; mucilage of starch, 1/2 pint. In ascarides, atonic amenorrh[oe]a, &c. It should not be employed when irritability of the rectum, bladder, or genitals, exists; nor in piles, or when there is a tendency to prolapsus ani or prolapsus uteri.
=Enema, An'odyne.= See ENEMA OF OPIUM.
=Enema, Antispasmod'ic.= _Syn._ ENEMA ANTISPASMODICUM, L. _Prep._ From tincture of assaf[oe]tida, 3 fl. dr.; laudanum, 30 to 60 drops; water gruel or barley water, 1/2 pint. In spasmodic affections of the bowels. (See _below_.)
=Enema of Assaf[oe]t'ida.= _Syn._ FETID CLYSTER, ANTISPASMODIC C.; ENEMA ASSAF[OE]TIDA (B. P.), E. F[OE]TIDUM (Ph. E. & D.), L. _Prep._ 1. (B. P.) Assaf[oe]tida, 30 gr.; water, 4 oz.; rub together until mixed.
2. (Ph. E.) To cathartic enema (Ph. E.), add of tincture of assaf[oe]tida, 2 fl. dr.
3. (Ph. D.) Warm water, 12 fl. oz.; tincture of assaf[oe]tida, 2 fl. dr.
4. (St. B. Hosp.) Assaf[oe]tida, 2 dr.; yolk of an egg; barley water, 7 fl. oz. Stimulant, antispasmodic, and carminative. An excellent remedy in hysteria, flatulent colic, hooping-cough, infantile convulsions, worms in the lower bowels, &c. See ENEMA HOOPING-COUGH.
=Enema, Astrin''gent.= _Syn._ ENEMA ASTRINGENS, L. _Prep._ 1. Tincture of catechu, 1 fl. oz.; barley water, 9 fl. oz.
2. Extract of rhatany, 2 dr.; syrup, or made starch, 2 oz.; water, 7 fl. oz.
3. Decoction of galls, oak-bark, pomegranate, or other like astringent substance, 3 or 4 fl. oz.; water or barley water, 6 or 7 fl. oz.
4. (Hosp. F.) Electuary of catechu, 2 dr.; water and lime water, of each 4-1/2 fl. oz. In diarrh[oe]a, &c., arising from a relaxed condition of the coats of the lower bowels; and in fissures of the anus, &c.
=Enema of Bark.= _Syn._ ENEMA CINCHONÆ. Decoction of bark is used.
=Enema of Belladonna.= _Syn._ ENEMA BELLADONNÆ (Ratier.) _Prep._ Belladonna, 10 gr.; water, 6 oz.; infuse.
=Enema of Cam'phor.= _Syn._ ENEMA CAMPHORÆ, L. _Prep._ 1. Camphor liniment, 4 fl. dr.; yolks of 2 eggs; water gruel, 7 fl. oz.
2. Camphor, 1 dr.; rectified spirit, 2 dr.; triturate till dissolved, then add, gradually, of simple syrup, 1 oz.; when thoroughly incorporated, further add of thin gruel, 7 fl. oz. Anodyne, antispasmodic, and diuretic. In difficult or obstructed micturition.
=Enema of Cas'tor Oil.= _Syn._ ENEMA OLEI RICINI, L. _Prep._ 1. (Hosp. F.) Castor oil and mucilage, of each, 1 oz.; gruel, 1/2 pint.
2. Castor oil, 1 oz.; liquor potassa, 2 fl. dr.; triturate, and add of honey, 1 oz.; when mixed, further add of hot gruel, 1/2 pint; and agitate until cool enough to be administered.
=Enema, Cathar'tic.= _Syn._ PURGATIVE CLYSTER; ENEMA CATHARTICUM (B. P., Ph. E. & D.), E. LAXATIVUM, E. PURGATIVUM, L. These have been already alluded to. By increasing the quantity of the active ingredients, a mild laxative or aperient clyster is converted into an active purgative or cathartic one.
_Prep._ 1. (Ph. E.) Senna, 1/2 oz.; boiling water, 16 fl. oz.; infuse an hour, then add of Epsom salts, 1/2 oz.; sugar, 1 oz.; when dissolved, further add of olive oil, 1 oz.; and mix them by agitation.
2. (Ph. D.) Epsom salts, 1 oz.; olive oil, 1 fl. oz.; mucilage of barley. 16 fl. oz. Same as enema of sulphate of magnesia, B. P., except that in the latter mucilage of starch is substituted for mucilage of barley.
3. (Ph. D. 1826.) Manna, 1 oz.; compound decoction of chamomile, 1/2 pint; dissolve, and add, of olive oil, 1 oz.; Epsom salts, 1/2 oz.
4. Compound decoction of mallows, 1/2 pint; Epsom salts, 3/4 oz.; sweet oil, 2 fl. oz.; mix, as above.
_Obs._ The above are employed in all ordinary cases where the use of an immediate cathartic is indicated.
=Enema of Cevidina.= _Syn._ ENEMA CEVIDINÆ (Soubeiran.) Cevadilla, 2 dr.; water, 10 oz.; boil to 7 oz.; strain and add milk, 8 oz. To destroy ascarides.
=Enema of Chlo''ride of Lime.= _Syn._ ENEMA CHLORIDI CALCIS, E. ANTIPUTRESCENS, L. _Prep._ 1. Chloride of lime, 10 gr.; tepid water, 1 fl. oz.; triturate, then add of barley water, or plain tepid water, 7 fl. oz.
2. (Pereira.) Chloride of lime, 10 to 15 gr., added to a common enema. As a deodoriser, when the alvine evacuations are unusually fetid.
=Enema of Chloride of Soda.= _Syn._ ENEMA SODÆ CHLORINATÆ. _Prep._ Labarraque's solution, 24 drops; decoction of mallows, 16 oz.
=Enema of Chloride of Sodium.= _Syn._ ENEMA SODII CHLORIDI. _Prep._ Common salt, 1 oz.; barley water, 1/2 pint; olive oil, 1 oz.
=Enema for Col'ic.= _Syn._ ENEMA ANTICOLICUM, L. _Prep._ From oil of cajeput or peppermint, 15 drops; dissolved in sweet spirit of nitre, 60 drops; laudanum, 35 drops; infusion of chamomile, 1/2 pint.
=Enema of Col'ocynth.= _Syn._ ENEMA COLOCYNTHIDIS (Ph. L.), L. _Prep._ 1. (Ph. L.) Extract of colocynth, 1/2 dr.; soft soap, 1 oz.; triturate, and add of water, 1 pint.
2. (Ph. L. 1836.) As the last, but using compound extract of colocynth.
3. (Guy's Hosp.) Colocynth pulp, 1 dr.; water, 3/4 pint; boil so as to strain 1/2 pint; and add of common salt, 1/2 oz.; syrup of buckthorn, 1 fl. oz. An efficient enema in colic and obstinate constipation, in the absence of spasms and inflammatory symptoms.
=Enema, Com'mon.= _Syn._ ENEMA COMMUNE, L. Gruel or barley water, either with or without the addition of a little common salt or oil, are generally so called. The first are simply laxative; the latter, purgative. Decoction of mallows, linseed tea, or water gruel, are also commonly used as the vehicle.
_Prep._ 1. (St. Bar. Hosp.) Barley water, 1 pint; common salt, 1 oz.; dissolve.
2. (Guy's Hosp.) Water gruel, 10 to 15 fl. oz.; common salt, 1 oz.
3. (U. C. Hosp.) Water gruel, 8 to 12 fl. oz.; salt, 1 oz.; linseed oil, 2 fl. oz.
=Enema of Copai'ba.= _Syn._ ENEMA COPAIBÆ, L. _Prep._ 1. From balsam of copaiba, 2 dr.; liquor opii sedativus, 15 drops; yolk of egg, q. s.; barley water, 7-1/2 fl. oz.
2. (Collier.) To the last add, of extract of opium, 1 gr.; oil of turpentine, 4 fl. dr.
3. (Velpeau.) Copaiba, 2 dr.; laudanum, 20 drops; yolk of 1 egg; water gruel, 8 fl. oz. In ascarides, gonorrh[oe]a, and some affections of the lower bowels and bladder, when the stomach rejects the balsam.
=Enema of Creosote.= _Syn._ ENEMA CREOSOTI. (Dr Wilmot.) Creasote, 1 dr.; decoction of starch, 12 oz. In epidemic dysentery.
=Enema of Croton Oil.= _Syn._ ENEMA OLEI CROTONIS. (Sundelin.) _Prep._ Croton oil, 2 to 4 drops; linseed oil, 2 oz.; gruel, 4 oz.
=Enema of Cubebs.= _Syn._ ENEMA CUBEBÆ. (Velpeau.) _Prep._ Decoction of mallow, 10 oz.; powdered cubebs, 6 dr.
=Enema, Domes'tic.= _Syn._ ENEMA DOMESTICUM, L. This name has been applied to an enema of warm water, either with or without the addition of a little sugar, honey, or milk. The effect is laxative.
=Enema, Emoll'ient.= _Syn._ ENEMA EMOLLIENS, E. DEMULCENS, L. _Prep._ From decoction of linseed, barley, or starch, 1 pint; linseed or olive oil, 1 oz. Soothing and laxative; in excoriations of the lower bowels. 20 to 40 drops of laudanum may be added when there is much pain or looseness.
=Enema of Ergot.= _Syn._ ENEMA ERGOTÆ. (Boudin.) _Prep._ Infuse 1 dr. of ergot in 8 oz. of hot water and strain.
=Enema, Feb'rifuge.= _Syn._ ENEMA FEBRIFUGUM, L. _Prep._ 1. (Collier.) Water gruel, 12 fl. oz.; sugar, 1 fl. oz. In low fevers.
2. (Brande.) Vinegar, 2 fl. oz.; infusion of chamomile, 5 or 6 fl. oz. In typhus.
=Enema, Fe'tid.= See ENEMA OF ASSAF[OE]TIDA.
=Enema of Galls and Opium.= _Syn._ ENEMA GALLÆ ET OPII. (Dr Ryan.) _Prep._ Decoction of galls, 8 oz.; tincture of opium, 1/2 dr.
=Enema for Hoo'ping-cough.= _Syn._ ENEMA PERTUSSICULAIRE, L. _Prep._ 1. See ENEMA ASSAF[OE]TIDA.
2. (M. Reiken). Assaf[oe]tida, 8 gr.; yolk of 1 egg; water, 1/2 pint.
_Obs._ This quantity is sufficient for 10 or 12 clysters for children under 1 year; 5 or 6 for those under 3 years; and 2 or 3 for those under 7. Two clysters are prescribed daily in hooping-cough. According to M. Reiken, this is more successful in removing hooping-cough than any other remedy. To ensure success, it should not be administered until the feverish symptoms have passed. M. Reiken sometimes uses an ointment of assaf[oe]tida as well as the clyster.
=Enema of Ipecacuanha.= _Syn._ ENEMA IPECACUANHÆ. (U. C. Hosp.) Ipecacuanha root (bruised), 1 dr.; boiling water, 8 oz. Macerate for an hour and strain.
=Enema, Lax'ative.= See ENEMAS (Cathartic, Common, &c.).
=Enema of Lead.= _Syn._ ENEMA PLUMBI, L. _Prep._ (Dr Newbold.) Acetate of lead, 6 gr.; tepid distilled water, 6 fl. oz. In strangulated hernia; repeated in two or three hours.
=Enema of Morphia.= _Syn._ ENEMA MORPHIÆ. (Beera.) _Prep._ Morphia, 1 gr.; oil of almonds, 1 oz. Triturate and add infusion or decoction of linseed, q. s.
=Enema, Nitrate of Silver.= _Syn._ ENEMA ARGENTI NITRATIS. (Boudin.) _Prep._ Nitrate of silver, 1 to 3 gr.; distilled water, 5 oz.
=Enema, Nu'trient.= _Syn._ FEEDING CLYSTER; ENEMA NUTRIENS, L. _Prep._ 1. Strong beef tea, 12 fl. oz.; thickened a little with arrow-root or hartshorn shavings.
2. (M. Nasse). Strong meat soup, 3/4 pint; dilute hydrochloric acid, 1/2 fl. dr.
3. Yolks of 2 eggs; brown sugar and salad oil, of each 1 oz.; mutton broth, 12 fl. oz. To nourish the body, when aliments cannot be taken or retained by the stomach.
=Enema, Oi''ly.= See ENEMA (Emollient).
=Enema of O'pium.= _Syn._ ENEMA OPIATUM, E. OPII (B. P. and Ph. L.), E. OPII vel ANODYNUM (Ph. E.), L. _Prep._ 1. (B. P.) Mucilage of starch, 2 fl. oz.; tincture of opium, 1/2 dr.
2. (Ph. E.) Starch, 1/2 dr.; water (boiling), 2 fl. oz.; mix, and when cool enough add of tincture of opium, 1/2 to 1 fl. dr.
3. (Ph. D. 1826.) Laudanum, 1 dr.; warm water, 6 fl. oz.
_Obs._ The above are the orders of the colleges, but in practice the quantity of laudanum is frequently doubled; this should, however, be done with great care. Opium clysters are used in dysentery, colic, cholera, and various painful affections of the intestines, bladder, &c. The bowels should be emptied before their administration, and in inflammatory complaints they should not be used for the first 48 hours. Clysters containing opium, even in small quantities, are dangerous remedies for young children; yet there are cases in which they sometimes succeed when every other remedy has failed. This is particularly so in the low chronic diarrh[oe]a of infancy and early childhood. A case of this kind occurred in the family of the writer. The family medical attendant, as well as the physician he consulted, abandoned the little sufferer to apparently inevitable death, as beyond the reach of further assistance. A small opium clyster was given, and the child recovered.
=Enema of Ox-gall.= _Syn._ ENEMA FELLIS, E. F. BOVIS, L. _Prep._ (Dr Allnatt.) Fresh ox-gall, 2 fl. oz.; water gruel, 8 fl. oz.
2. (Dr Clay.) Ox-gall, 2 fl. oz.; water, 4 or 5 fl. oz. To soften indurated fæces, and in costiveness arising from deficiency of bile.
=Enema of Percyanide of Iron.= _Syn._ ENEMA FERRI PERCYANIDI. _Prep._ Triturate 5 gr. of Prussian blue, with 2 oz. of water; to be used daily, increasing the dose if necessary. An American remedy for ascarides.
=Enema of Pop'pies.= _Syn._ ENEMA PAPAVERIS, L. _Prep._ 1. DECOCTION OF POPPIES.
2. Poppy-heads (with the seeds), 5 dr.; water, 3/4 pint; boil to 12 fl. oz., and strain. Anodyne; as a substitute for opium clyster.
=Enema, Pur'gative.= See ENEMA CATHARTIC.
=Enema of Quinine.= _Syn._ ENEMA QUINIÆ. Sulphate of quinine, 5 to 15 gr.; decoction of starch, 6 oz.
=Enema of Rue.= _Syn._ ENEMA RUTÆ. _Prep._ Confection of rue, 20 to 60 gr; thin gruel, 6 oz. to 8 oz.
=Enema, Sim'ple.= Barley water, rice water, thin-made starch, and decoction of mallows, are frequently so called, from being used either for simple laxative enemas, or as the vehicle for more active substances.
=Enema of Soap.= _Syn._ ENEMA SAPONIS, L. _Prep._ (St. B. Hosp.) Soft soap, 6 dr.; hot water, 1 pint; dissolve. To soften indurated fæces, &c.; and as a detergent in certain ulcerations of the rectum.
=Enema of Soot.= _Syn._ ENEMA FULIGINIS. Wood soot, 4 oz.; water, 1-1/2 pints; boil to a pint.
=Enema of Starch.= _Syn._ ENEMA AMYLI, L. See ENEMA SIMPLE (_above_).
=Enema, Stim'ulant.= _Syn._ ENEMA STIMULANS, L. The ordinary cathartic clysters are often so called. The following belong to a different class:--
_Prep._ 1. Tincture of capsicum, 1 fl. oz.; barley water or thin arrow-root, 1/2 pint; mix. In cholera, especially the cold stages.
2. To the last add, of ether, 2 fl. dr.; laudanum, 30 drops.
3. Decoction of poppies, 1/2 pint; tincture of capsicum, 3 fl. dr.; oil of nutmeg, 10 drops. In diarrh[oe]a.
=Enema of Tobac'co.= _Syn._ ENEMA TABACI (Ph. L. E. & D.), INFUSUM TABACI (Ph. D. 1826), L. _Prep._ 1. (B. P.) Tobacco leaf, 20 gr.; boiling water, 8 oz.; infuse half an hour, and strain.
2. (Ph. E.) Tobacco, 15 to 30 gr.; boiling water, 8 fl. oz.; as last.
3. (Ph. D.) Tobacco, 1 scrup.; boiling water, 8 fl. oz.
4. (Ph. L. 1836.) Tobacco, 1 dr.; boiling water, 1 pint.
_Obs._ Tobacco clyster is used in strangulated hernia, obstinate constipation, retention of urine, &c. It is violently depressing and relaxing; producing fainting, and even death, when improperly or injudiciously administered. "It is not to be forgotten that 2 dr., 1 dr., and even 1/2 dr., of tobacco, infused in water, have proved fatal." "The cautious practitioner, therefore, will not use more than 15 or 20 gr." (Pereira.) Three parts of Virginia tobacco are equal to seven parts of any other kind. (Davy.)
=Enema of Tur'pentine.= _Syn._ TURPENTINE CLYSTER; ENEMA TEREBINTHINÆ (Ph. L.), E. OLEI T., L. _Prep._ 1. (B. P.) Oil of turpentine, 1 oz.; mucilage of starch, 15 oz.
2. (Ph. L.) Oil of turpentine, 1 fl. oz.; yolk of 1 egg; triturate together, then add of decoction of barley, 19 fl. oz.
3. (Ph. E.) As the last, but using simple water instead of barley water.
4. (Ph. D.) Oil of turpentine, 1 fl. oz.; mucilage of barley, 16 fl. oz.
5. (Dr Neligan.) Oil of turpentine, 1/2 fl. oz.; syrup of garlic, 1 fl. oz.; barley water, 6 or 7 fl. oz. In ascarides, and as an antispasmodic and purgative in colic, obstinate constipation, calculus, peritonitis, tympanitis (DRUM-BELLY), &c.
=Enema, Ver'mifuge.= _Syn._ ENEMA ANTHELMINTICUM, E. VERMIFUGUM, L. _Prep._ 1. Castor oil, 1 oz.; mucilage, 3/4 oz.; decoction of the root of male fern, 7 fl. oz. In worms, especially tape-worm.
2. (Collier.) Oil of turpentine, 1 fl. oz.; olive oil (warm), 1/2 pint. In ascarides.
3. (Dr Darwall.) Tincture of sesquichloride of iron, 1 dr.; water, 7 or 8 fl. oz. In ascarides, especially when occurring in childhood; the quantity used being proportionately lessened. See ENEMAS of ALOES, ASSAF[OE]TIDA, TURPENTINE, &c.
=Enema of Vinegar.= _Syn._ ENEMA ACETICI. (Brande.) _Prep._ Vinegar, 2 oz.; infusion of chamomile, 4 oz. In typhus fever.
=Enema of Wine.= _Syn._ ENEMA VINOSUM, L. _Prep._ From sherry wine and hot water, of each 7 fl. oz. In suspended animation. Sometimes a wine-glassful of brandy is added.
=ENERGY, relative values of Food as sources of.= Chemists and physiologists, although they agree that muscular power is derived from the action of the oxygen supplied during respiration upon the digested portions of the food, differ in their conclusions as to whether the nitrogenous or non-nitrogenous principles of the food, form the chief source of this power or not. The opinion of Liebig, Playfair, Ranke, and others, that the oxidation and metamorphosis of the nitrogenous tissue is the fountain of muscular force has of late years been contested, and on the opposite view adduced, viz. that it is principally to the oxidation of the carbonaceous or non-nitrogenous constituents of the food, that animal dynamic power is due.
This latter view has received support from the experiments of Frankland, Lawes, and Gilbert (from their observations on the feeding of cattle), Edward Smith, Meyer, Pettenkofer, Voit, Wislicenus, Fick, Parkes, and others.
The data upon which it is based are those derived from the observation of the amount of heat generated by the combustion of a definite quantity of food out of the body; which, it is affirmed with certain deductions, represents the quantity of heat evolved by the oxidation of the same food within the body; and as heat is the equivalent of muscular force or energy, that aliment which, in burning, gives off the most heat, must, it is supposed, necessarily be the richest in the production of animal motive power. Of course these conditions will, amongst others, be very considerably modified by the extent to which the processes of the animal economy, such as digestion, assimilation, &c., can liberate the elements of the food so as to become available as sources of this energy.
Were these processes perfect, all the carbon of the carbonaceous, as well as that of the nitrogenous constituents of the diet, after deducting the carbon which passes off as urea (one part of dry nitrogenous matter yielding about a third of its weight of urea) would be utilised and converted into heat-producing power. But even under these circumstances a considerable portion of this thermotic power would be expended in sustaining the internal movements of the body, such as respiration and the heart's action, which it has been computed are daily maintained by a force capable of raising 600,000 pounds a foot high.
No wonder if, with such varying factors introduced into the problem, physiologists and physicists should differ so widely in their calculations; and that, whilst one inquirer believes that food practically yields only about half the force which, according to theory, it actually contains; another estimates it at only one fifth.