There are seldom great difficulties in this class of preparations. Lime-water to be mixed with oils should be added all at once, and well shaken. By adding gradually, a perfectly homogeneous combination is rarely attained. See that the lime-water is fresh and of full strength. Weak lime-water is generally the cause of failures.

The following are a few examples of exceptional difficulties. The first is a hair-lotion of the character of a liniment:

By a slight modification of the formula, this may be compounded as follows:

First add gradually the acetum cantharidis to the spirit of hartshorn (use the liquor vol. cornu cervi, and not liquor ammon., B.P.), constantly stirring with a glass rod until gas bubbles no longer rise, then rub thoroughly well the paraffinum molle (use vaseline) with the oleum olivae until a creamy compound is formed; afterwards gradually add, little by little, the partly neutralised liquor, constantly rubbing, adding lastly the eau de Cologne.

The prescribing of oils, lanoline, and vaseline in aqueous applications (embrocations or lotions) has now become popular with medical men. The following are typical examples:

The following is the best way to prepare a:

Stir the zinc oxide in a mortar with the lime-water; add the ichthyol (this has a remarkably thinning effect); now add the oil all at once, and triturate. This produces a nice thin cream of brown tint.

Mr. John Lothian found the following modus operandi to give the best results with b:

Triturate the mixed powders in a mortar with the olive oil and transfer to a wet wide-mouthed bottle; mix the liq. plumbi subacet. and the liq. calcis, add all at once, and shake vigorously ; a nice thick cream results. The calamine used was zinc carbonate coloured with Armenian bole.

Other examples:

Rub the powders with water ss. and heat with the linseed oil on a water-bath for half an hour, stirring well all the time; then gradually add the rest of the water, and, when cold, carbolic acid in requisite proportion.

In this case it is necessary to add soap. Dilute the B. P. ammoniated-mercury ointment with lard, add the powdered starch and pulv. saponis 3ij., mix well, and finally emulsify

, mix well, and finally emulsify with the lime-water.

Lanoline is intractable with more than its own weight of 'water, but soap and saponifying agents facilitate emulsion, 'creams' resulting:

Melt the fats in a warm bottle, add the liquor, and shake until cold.

To be painted on every night.

Rub the lanoline in a warm mortar with 2 drachms of powdered white soap, and gradually stir in 4 ounces of the almond mixture, slightly warmed. Mix the sublimed sulphur with the rest of the almond mixture (B.P., but made with bitter almonds), and add it gradually to the contents of the mortar.

Soap is a necessary addition in many cases, e.g.:

Put a drachm of powdered soap in a mortar, and mix the oil with it; then add the potassium-iodide liniment. Sooner or later the preparation becomes brownish in colour, owing to iiberation of iodine due to the ozonising effect of the essential oil.

Vaseline embrocations are exceedingly troublesome. The following prescription could not be compounded by a first-class house:

A fairly good cream was made by another dispenser in the following manner: Pour the melted vaseline into a warm bottle; add the powders, and shake; then add gradually 1/2 ounce of warm lime-water, shaking well, and gradually fill the bottle with cold lime-water, constantly shaking. The modus operandi is intended to comminute the vaseline thoroughly, and the gradual cooling helps to keep it in suspension.

We have never been able to make a satisfactory preparation of the following :

The best plan is to use vaseline oil (paraffinum liquidum, B.P.) in place of the vaseline, mixing in the order given.

A favourite prescription with some medical men is a mixture of belladonna extract and liniment, such as the following:

It is the green extract which is here intended, and when it is rubbed up with the liniment there is an abundant separation of chlorophyll and extractive matter, which cannot be avoided. Rub the extract in a mortar with 1/2 drachm of hot water; then gradually add the liniment and strain through a small piece of calico. This is how the prescription is generally dispensed. The active principles are retained in solution. If the liniment is dispensed unstrained, the suspended matter attaches itself to the sides of the bottle. The following are similar cases which should be treated in the same way:

In the case of a, mix the tincture of iodine and liniment of camphor before adding to the thinned extract.

Rub the extract with 1/2 ounce of solution of ammonia until solution is effected; then agitate with 1 1/2 ounce of olive oil.

Mixed in the above order, a good cream results.

Thin the extract with hot water, and add the oil gradually. Do not strain.

Melt the coconut oil with a gentle heat. Mix the rest of the ingredients and add to the oil, stirring assiduously until it sets.