III. Emulsion of Cod Liver Oil with Hypophosphite of Lime. - This differs from the simple emulsion in that 128 gr. of calcium hypophosphite are dissolved in the water, each tablespoonful of the finished emulsion containing 4 gr. of that salt.

IV. Emulsion of Cod Liver Oil with Hypophosphite of Lime and Soda. - This differs from the simple emulsion in that 128 gr. of calcium hypophosphite and 96 gr. of sodium hypophosphite are dissolved in the water, each tablespoonful of the finished emulsion containing 4 gr. of the calcium and 3 gr. of the sodium salt.

V. Emulsion of Cod Liver OH with Hypophosphites. - This differs from the simple emulsion in that 128 gr. of calcium hypophosphite, 96 gr. of sodium hypophosphite, and 64 gr. of potassium hypophosphite are dissolved in the water ; each tablespoonful containing 4 gr. of the calcium, 3 gr. of the sodium, and 2 gr. of the potassium salt, and corresponding to a teaspoon-ful of Churchill's syrup of the hypo-phosphites.

VI. Emulsion of Cod Liter Oil with Phosphate of Lime. - This differs from the simple emulsion in that 256 gr. of calcium phosphate are dissolved in the water by the aid of 128 gr. of hydrochloric acid,* each tablespoonful containing 8 gr. of the phosphate held in pleasantly acid solution.

VII. Emulsion of Cod Liver Oil with Phosphate of Lime and Soda. - This differs from the simple emulsion in that 256 gr. of calcium phosphate and 64 gr. of sodium phosphate are dissolved in the water acidulated with 128 gr. of hydrochloric acid; each tablespoonful containing 8 gr. of the calcium and 2 gr. of the sodium salt.

VIII. Emulsion of Cod Liver Oil with Lactophosphate of Lime. - This differs from the simple emulsion in that 256 gr. of calcium lactate dissolved in 2 fl. oz.. of diluted phosphoric acid are substituted for 2 fl. oz. of the water, each tablespoonful containing 8 gr. of lime lactate or about 10 gr. of lactophosphate.

IX. Emulsion of Cod Liver Oil with Wild Cherry Bark. - This differs from the simple emulsion in that the oil of wintergreen is replaced by 8 drops of oil of bitter almonds and in that 1 fl. oz, of the fluid extract of wild cherry bark is substituted for 1 fl. oz. of the water; each tablespoonful containing 15 minim of the fluid extract and one-fourth of a drop of oil of bitter almonds.

Other combinations of cod liver oil with different medicinal agents may be effected in the same way as pointed out in the above, or the proportions of salts may be varied to suit particular cases. The process for the concentrated emulsion also may be applied to the emulsifi-cation of other oils, as, for instance, in the following:

X. Emulsion of Castor Oil. - Take of castor oil, 4 oz.; powdered gum arabic, 1 oz.; distilled water, 1 1/2 oz.; syrup, cinnamon water, of each 3 fl. oz.; spirit of cinnamon, 12 minims. Emulsify the oil with the gum and distilled water as directed under I., then add the other ingredients successively with constant trituration. This emulsion contains 33 per cent. of castor oil, and is consequently more limpid than the 50 per cent. cod liver oil emulsions above described, and is in every respect an elegant preparation. (C. Lewis Diehl.)

A useful contrivance for making photographers' emulsions is shown in Fig. 117: a, funnel with tuft of cotton wool in its throat, serving to filter the inflowing water; 6, guttapercha bung;

* The use of hydrochloric add instead of phosphoric acid is preferred, because the large quantity of the latter required would make the preparation unpleasantly sour.

c. jampot provided with a hole to carry a cork, holding an indiarubber tube d; e, muslin bag retained in position by the bung, and containing the fragments of emulsion.

Fig. 117.

Fro. 118.

Emulsifying Part 4 400133

Another excellent apparatus for making gelatine emulsions for photographic purposes is that introduced by Birrell, and illustrated in Fig. 118. This apparatus is placed under a tap, the water being allowed to flow in at about the same rate as it will flow through the filtering medium in the funnel. Instead, however, of using cotton-wool for the purpose of filtering the inflow water, it is more convenient to tie a piece of muslin over the stem of the funnel as shown in the subjoined diagram, this method of arranging a filter having been recommended by Colonel Dawson in another case. All string and muslin used should be cleansed before use by boiling in soda and subsequent washing, as recommended in respect to the canvas; and it is undesirable to use either of such materials a second time when one is making a highly sensitive emulsion. The washing being completed, the muslin strainer is removed from the jar, and, the edges being gathered together, the whole is swung round a few times to drive off the loosely held water; but, notwithstanding this, it is extremely probable that the fine shreds of emulsion will have absorbed so much water as to make the preparation inconveniently weak when melted, and the test of this is to weigh the product.

A clean beaker of suitable size is balanced on the scale-pan, and a piece of wet muslin corresponding to that used for retaining the emulsion is placed in the weight-pan. The square of muslin containing the emulsion should now be tied up blue-bag fashion, placed in the beaker, and weighed. If it weighs more than 750 grm. (26 1/2 oz.), it is well to remove some of the water - a very easy matter if the bag be dipped in alcohol - and moved about for a few minutes, after which it is once more swung round to drive off the redundant water and again weighed.