Amount of Rectified Spirit required to make Dilute Alcohol with the water contained in each ounce of moist magma, and strength of tinctures resulting from plants containing over 84 per cent. of moisture.

Moisture lost in drying.

Rectified Spirit required.

Fl. oz.

Strength of

Tincture.

Fl. oz.

85 per cent. ..............

0.85 .........

1 in 11.00

86 „ ...................... ........

0.86 .........

1 „ 11.93

87 „ ...................... ........

0.87 .........

1 „ 13.00

88 „ ...................... ........

0.88 .........

1 „ 14.25

89 „ ...................... ........

0.89 .........

1 „ 15.73

90 „ ...................... ........

0.90 .........

1 „ 17.50

91 „ ...................... ........

0.91 .........

1 „ 19.67

92 „ ...................... ........

0.92 .........

1 „ 22.37

93 „ ...................... ........

0.93 .........

1 „ 25.86

94 „ ......................

0.94 .........

1 „ 30.50

As an example of the method of using the Tables, take the following case: -

Suppose a specimen of fresh Aconite has been reduced to pulp, and the 100 grains have lost 69 grains in drying; then by reference to the Pharmacopoeia it will be seen that proof spirit is directed for this tincture. Now, on referring to Table No. 3, it will be found that 1 ounce of moist magma, containing 70 per cent. (the nearest to 69)* of water, requires 1.08 fluid ounce of rectified spirit to form proof spirit with the water contained in it, and this quantity multiplied by 4, gives 4.32 fluid ounces, or the quantity required for the like conversion of the water contained in the 4 ounces of moist magma; hence that amount of rectified spirit must be first poured into a bottle; and as, by reference to Table 3, it will be seen that 1.27 fluid ounce of proof spirit is required to be added for each ounce of moist magma to make a tincture representing 10 per cent. of the dry material where the fresh plant contains 70 per cent. of water, four times this amount, or 5.08 fluid ounces, of proof spirit must be added. This mixed spirit will then be used as directed for making the tincture, and the result will be a tincture of the alcoholic strength of proof spirit, and will represent 1 grain of dry Aconite in every 10 minims of the tincture; and, for reasons before stated, proof spirit should be used for making the first decimal attenuation.

* Five per cent. is the smallest amount of moisture which need be noticed practically when dealing with 4 ounces or upwards, if the loss is below 70 per cent.; hence, when the amount lost is between the percentages stated, the figures should be taken which come nearest to the exact loss.

The alcoholic solutions (tinctures) of animal substances are, with few exceptions, merely solutions in ten times the quantity by measure of spirit of the strength directed. A few, such as Cantharis, are prepared by percolation, and in that case they are treated in precisely the same way as vegetable substances.