Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 214

RED SNUFF. As last, but using red ochre.

=Snuff, Asarabac'ca.= _Syn._ CEPHALIC SNUFF, COMPOUND POWDER OF ASARABACCA; PULVIS ASARI COMPOSITUS, L. _Prep._ 1. (Ph. D. 1826.) Asarabacca leaves, 1 oz.; lavender flowers, 1 dr. (both dried); mix and powder them.

2. (Ph. E. 1817.) Asarabacca leaves, 3 dr.; leaves of marjoram and flowers of lavender, of each 1 dr.; as before. Both are used as errhines in headaches and ophthalmia. See SNUFF, CEPHALIC, ASARABACCA, &c.

=Snuff, Cephal'ic.= _Prep._ 1. From asarabacca leaves and Lundyfoot snuff, of each 2 oz.; lavender flowers, 1/4 oz.; essence of bergamotte and oil of cloves, of each 2 or 3 drops; mixed and ground to a powder, the perfume being added last.

2. (Boeli's.) From tobacco or pure snuff and valerian root, of each 1/2 oz.; reduced to powder, and scented with the oils of lavender and marjoram, of each 5 or 6 drops.

_Obs._ The first formula is an excellent one; and the product is very useful in nervous headaches, dimness of sight, &c. See SNUFF, ASARABACCA (_above_).

=Snuff, Eye.= _Prep._ From finely levigated tribasic sulphate of mercury ('Turpeth mineral'), 1/2 dr.; pure dry Scotch or Lundyfoot snuff, 1 oz.; triturate them well together. A pinch of this, occasionally, has been recommended in inflammation of the eyes, dimness of sight, headache, polypus, &c.; but it should be used with caution, and not too often.

=SOAP.= _Syn._ SAPO, L.; SAVON, Fr. SPANISH, CASTILE, or HARD SOAP, made with olive oil and soda (SAPO, SAPO EX OLIVae OLEO ET SODa CONFECTUS--Ph.

L.; SAPO DURUS--B. P., Ph. E., & D.), and SOFT SOAP, made with olive oil and potash (SAPO MOLLIS--B. P., Ph. L., & E., SAPO EX OLIVae OLEO ET POTa.s.sa CONFECTUS--Ph. L.), are the only kinds directed to be employed in medicine. The former is intended whenever 'soap' is ordered, and is the one which is princ.i.p.ally employed internally; the latter is used in ointments, &c., and in some of the officinal pills.

_Prep._ The fatty or oleaginous matter is boiled with a weak alkaline lye (soap-lye) rendered caustic by quicklime, and portions of stronger lye are added from time to time, the ebullition being still continued, until these substances, reacting on each other, combine to form a tenacious compound, which begins to separate from the water; to promote this separation and the granulation of the newly-formed soap, some common salt is generally added, and the fire being withdrawn, the contents of the boiler are allowed to repose for some hours, in order that the soap may collect into one stratum, and solidify; when this happens it is put into wooden frames or moulds, and when it has become stiff enough to be handled it is cut into bars or pieces, and exposed to the air, in a warm situation, to further harden and to dry.

In the print works of Alsace, where an immense quant.i.ty of egg alb.u.men is consumed, there collect, as a necessary result, enormous quant.i.ties of the yolks of egg. Amongst other purposes to which these are applied that of soap-making is one. According to Kingzett, the olein is not the only ingredient of the yolk which reacts upon the soda or potash, and thus produces soap; but the yolk also contains another body, which, absorbing water under the influence of the bases, splits up into oleic and margaric acids.

"Besides the olein contained in the free state, there is," says Mr Kingzett, "present a body called _lecithine_ of the formula C_{42}H_{84}NPO_{9}." Gobloy, Diakonow, Strecker, Thudic.u.m, and Kingzett have studied this substance, and express its chemolysis as follows:--

Lecithine. Water. Glycero-phosphoric acid.

C_{42}H_{84}NPO_{9} - 3H_{2}O = C_{3}H_{9}PO_{6}

Choline. Oleic acid. Palmitic acid.

+ C_{5}H_{15}NO_{2} + C_{18}H_{34}O_{2} + C_{16}H_{32}O_{2}.

That is to say, bases have the power, by abstracting water, to split up _lecithine_ into, among other products, oleic and palmitic acid; so that when eggs are used for soap-making this process actually occurs, the soda or potash employed being sufficient to effect the necessary decomposition, and the resulting soap being, therefore, the product from not only the olein, but from the fatty acids so formed.

Tessie du Mothay has proposed a method for the recovery of potash, soda, &c., from soap water, which is as follows:--He decomposes the soap water by calcium, barium, or magnesium carbonate, and then pa.s.ses carbonic acid through the liquid. The bicarbonate form precipitates organic matter and other impurities, and these settle down. The solution is then evaporated or treated with baryta water, which precipitates the last portion of foreign matters, and leaves a solution of caustic alkali. At a particular stage of the process an acid is used in order to hasten the separation of the resinous substances, and, in certain cases, of the sulphides of sodium and calcium, or barium and calcium and ferric oxide, and then pa.s.ses carbonic acid into the liquid. The precipitated metallic substances carry down with them the humus-like substances present.

_Var._ The princ.i.p.al varieties of soap found in commerce are:--

ALMOND SOAP (SAPO AMYGDALINUS), made from almond oil and caustic soda, and chiefly used for the toilet.

The P. Codex gives the following formula for its preparation:--Solution of caustic soda (1334), by weight, 10 oz.; oil of almonds, by weight, 21 oz.; add the lye to the oil in small portions, stirring frequently; leave the mixture for some days at a temperature of from 64 to 68 Fahr., stirring occasionally, and when it has acquired the consistence of a soft paste, put it into moulds until sufficiently solidified. It should be exposed to the air for one or two months before it is used.

ANIMAL SOAP. SAPO ANIMALIS, CURD SOAP (B. P.). A soap made with soda and a purified animal fat consisting princ.i.p.ally of stearin (P. Cod.). Put 5 parts of beef marrow with 10 parts of water into a porcelain or silver basin, heat, and when melted add by portions, with constant stirring, 2-1/2 parts of liquor sodae (133); when saponified, add 1 part of salt; stir, remove the soap from the surface, drain it, melt it with a gentle heat, and pour it into moulds.

CASTILE SOAP, SPANISH S., Ma.r.s.eILLES S.; SAPO CASTILIENSIS, SAPO HISPANICUS. An olive-oil soda soap, kept both in the white and marbled state. The former is said to be the purest, the latter the strongest.

CURD SOAP, made with tallow (chiefly) and soda (see _above_).

MEDICATED SOAPS, containing various active ingredients. The chief of these are noticed _below_.

MOTTLED SOAP, made with refuse kitchen-stuff, &c.

SOFT SOAP (of commerce), made with whale, seal, or cod oil, tallow, and caustic potash.

N. Grager[172] gives the following method for the easy determination of the fat and alkali in soft (potash) soaps:--25 to 50 grammes of soap are dissolved in 150 c.c. of water by aid of heat, cooled, and mixed with an excess of salt, so that a soda-soap separates out; the latter is washed on a paper filter with a saturated solution of salt. In the filtrate the free alkali is estimated by a normal acid. The precipitate is decomposed by warming with excess of normal acid, and the quant.i.ty of acid neutralised by the combined alkali, determined by a standard soda solution. The cake of fat which separates in the last operation, is dried and weighed after adding to it, while melted, a known weight of stearin or paraffin to give it hardness.

[Footnote 172: 'Dingler's Journal' ('Journ. of Chem. Soc.,' vol. ix, new]

TOILET SOAPS, prepared from any of the preceding varieties, and variously coloured and scented. Formulae are given _below_.

YELLOW SOAP, RESIN SOAP, made with tallow, resin, and caustic soda.

Soluble gla.s.s is now largely employed in place of resin.

Soaps are also divided into SOFT or POTASH SOAPS, and HARD or SODA SOAPS.

_a.s.say._ 1. For the WATER. A piece, fairly taken from the sample, and weighing 100 gr., is reduced to thin shavings, which are dried by the heat of boiling water, until they cease to lose weight. The loss indicates the proportion of free water. This should not exceed 35% for ordinary curd and mottled soap, 45% for yellow soap, and about 15% to 16% for Castile soap.

2. For the ALKALI. 100 gr. of the soap are dissolved in 4 or 5 fl. oz. of boiling water, and the solution tested by the common method of alkalimetry. Curd and yellow soap usually contain from 6% to 7%, mottled soap from 7% to 8%, and Castile soap 8% to 9% of soda.

3. For the OIL or FAT. The solution tested for alkali (see No. 2) is heated, and then allowed to cool slowly; when cold the floating fatty matter is removed, freed from water, and weighed. When the fat or oil has little consistence, 100 gr. of pure white wax is added to the soap solution before heating it. The weight obtained, in grains in the one case, and the excess above 100 gr. in the other, give the proportion of oil or fat present. This, in ordinary mottled soap, should be about 68%; in yellow soap, 65%; in curd soap, 60%; and in Castile soap, 75%.

4. UNSAPONIFIED FATTY MATTER.--_a._ Pure soap is entirely soluble in distilled water and insoluble in saline solution; if a film of fatty matter forms on its solution in the former, after repose, that portion has not been saponified.

_b._ The fat separated from soap (see No. 2), when it has been perfectly saponified, is entirely soluble in alcohol.

5. OTHER IMPURITIES. Pure soap is soluble in rectified spirit, forming a colourless or nearly colourless solution. The undissolved portion, if exceeding 1%, is adulteration.

ANOTHER METHOD OF SOAP a.s.sAY (M. Moffit). The const.i.tuents to be determined in an a.n.a.lysis of soap are alkalies (combined and free), carbonates, fatty acids, resin, glycerin, salts, colouring matters, and water.

Three portions of the finely divided soap are weighed off, containing respectively 10 grams, 20 grams, and 40 grams. Ten grams are digested with alcohol on the water-bath and filtered. The residue containing carbonates and other salts, colouring matter, &c., is dried at 100, weighed, digested with water, and t.i.trated with normal oxalic acid. Every c.c. of acid used indicates 0053 Na_{2}CO_{3}.

Regard must be had to a slight precipitate of calcium oxalate. The weight of Na_{2}CO_{3} found is subtracted from the total residue insoluble in alcohol, the difference is the weight of the salts and foreign matters.

The filtrate is subjected to a stream of carbonic acid, filtered, and the precipitate dissolved in water and t.i.trated with oxalic acid. Each c.c.

of acid indicates 0031 free soda, or 0042 free potash. No precipitate shows the absence of free alkalies. The filtrate from the precipitate produced by the carbonic acid is, after the addition of 15 c.c. of water, evaporated to remove the alcohol. The aqueous solution, treated with normal oxalic acid to acid reaction, shows for every c.c. of acid 0031 soda, or 0042 potash in combination. Sulphuric acid is then added, and the whole is heated on a water bath with pure beeswax to separate the fatty acids and resin, which are then weighed, the weight of the beeswax being subtracted.

Forty grams of the soap are next dissolved in water and mixed with sulphuric acid, as long as any precipitate is formed. On standing the fatty acids separate, and can be dried and weighed. These fatty acids are digested with a mixture of equal volumes of water and alcohol, till the liquid on cooling ceases to appear milky. The solid layer is again weighed, and the difference between the weight and that obtained above shows the weight of the resin.

The melting point of the acids is next determined. Ten grams are then dissolved in alcohol, and sulphuric acid diluted with alcohol is added, till a precipitate is no longer formed. The liquid is filtered, mixed with barium carbonate, and again filtered. The sweet residue left after evaporation of the alcohol is glycerin. The weights of the carbonates, salts, and foreign matters, free and combined alkalies, fatty acids, resin, and glycerin are added together, and the sum subtracted from 10 grams gives the weight of the water.

See also Soap a.n.a.lysis, 'Chem. News,' x.x.xv, 2. The article is too long to allow of insertion here.

_Uses, &c._ The common uses of soap need not be enumerated. As a medicine it acts as a mild purgative and lithontriptic, and it has been thought by some to be useful in certain affections of the stomach arising from deficiency of bile. _Externally_ it is stimulant and detergent.--_Dose_, 3 to 20 or 30 gr., made into pills, and usually combined with aloes or rhubarb.

_Concluding Remarks._ Prior to the researches of Chevreul, no correct ideas were entertained as to the const.i.tution of soap. It was long known that the fixed oils and fats, in contact with caustic alkaline solutions at a high temperature, undergo the remarkable change which is called saponification; but here the knowledge of the matter stopped. Chevreul discovered that if the soap, so produced, be afterwards decomposed by the addition of an acid, the fat which separates is found to be completely changed in character; to have acquired a strong acid reaction when applied in a melted state to test paper, and to have become soluble with the greatest facility in warm alcohol; in other words--that a new substance, capable of forming salts, and exhibiting all the characteristic properties of an acid, has been generated out of the elements of the neutral fat under the influence of the base. Stearin, when thus treated, yields stearic acid, palmitin gives palmitic acid, olein gives oleic acid, and common animal fat, which is a mixture of several neutral bodies, affords, by saponification by an alkali and subsequent decomposition of the soap, a mixture of the corresponding fatty acids. These bodies are not, however, the only products of saponification; the change is always accompanied by the formation of a very peculiar sweet substance called glycerin, which remains in the mother liquor from which the acidified fat has been separated. The process of saponification itself proceeds with perfect facility, even in a closed vessel; no gas is disengaged; the neutral fat, of whatsoever kind, is simply resolved into an alkaline salt of the fatty acid, which is soap, and into glycerin, a neutral body resembling syrup, and, like that liquid, miscible with water in every proportion.

"When yellow soap is made with the cheaper kinds of fat it will hardly acquire a sufficient degree of firmness or hardness to satisfy the thrifty washerwoman. It melts away too rapidly in hot water, a defect which may be well remedied by the introduction into the soap of a little (120th) fused sulphate of soda; and this salt concreting gives the soap a desirable hardness, whilst it improves its colour, and renders it a more desirable article for the was.h.i.+ng tub." (Ure.) This process was patented by Dr Normandy, but soon proved a source of annoyance and molestation to him on the part of the Board of Excise, it being an enormous crime in law to attempt to improve and cheapen soap.

"Soda which contains sulphurets is preferred for making mottled or marble soap, whereas the desulphuretted soda makes the best white curd soap."

"The Barillas always contain a small proportion of potash, to which their peculiar value, in making a less brittle or more plastic hard soap than the fact.i.tious sodas, may, with great probability, be ascribed." (Ure.)

The mottled appearance is usually given, in the London Soap-works, by watering the nearly finished soap with a strong lye of crude soda, by means of a watering can furnished with a rose spout. For 'Castile soap' a solution of sulphate of iron is so employed. See SOAPS (Medicated and Toilet).