Extracts - or "solid " extracts, as they are termed, to distinguish them from fiuidextracts - are the soluble principles of vegetable drugs, extracted and concentrated by evaporation to a soft solid or a plastic mass of pilular consistence, or dried and reduced to powder.

Table Showing the Drug-strength and the Average Doses of the Official Extracts.

Extractum.

Part.

Parts of Drug in part of Extract (Approximate.)

Dose of Extract.

Grains.

Gm.

Aloes (aqueous)............................

2

2

0.125

Belladonnae Fol............................

Leaves...........

5

1/5

0.01

Cannabis Indicae.........................

Herb...............

10

1/5

0.01

Cimcifugae.................................

Rhizome.........

10

4

0.25

Colchici Cormi (acetic).............

Corm..............

3

1

0.065

Colocynthidis (powder)

Fruit................

6

1/2

0.03

Colocynthidis Com- Ext. Colocynth, 16; Carda-

Positum (powder) mom, 6; Aloes, 50; Soap,

Scammony, each, 14.

.....

7 1/2

0.5

Digitalis.....................................

Leaves ...........

4

1/2

0.01

Ergotae.....................................

Sclerotium......

8

4

0.25

Euonymi..................................

Bark...............

4

2

0.125

Gentinae (aqueous).................

Root................

4

4

0.25

Glycyrrhizae (stick)................

Root...............

3

15

1.

Glycyrrhizae Purum (ammon)...........

Root................

3

15

1.

Haematoxyli (aqueous0..................

Logwood.........

4

15

1.

Hyoscyami......................................

Herb................

6

1

0.065

Krameriae (aqueous)......................

Root................

5

7 1/2

0.5

Leptandrae........................................

Root.................

4

4

0.25

Malti................................................

Liquid ............

...

3 iv

16 Cc.

Nucis Vomicae (powder)...............

Seed................

10

1/4

0.015

Opii (powder)................................

.......................

1 1/2

1/2

0.03

Physostigmatis..............................

Calabar bean

20

1/8

0.008

Quassiae (aqueous)......................

Wood .............

10

1

0.065

Rhamni Purshianae.......................

Bark................

4

4

0.25

Rhei.............................................

Root................

3

4

0.25

Scopolae......................................

Rhizome.........

5

1/5

0.01

Stramonii.....................................

Leaves............

10

1/5

0.01

Sumbul......................................

Rhizome.........

..

4

0.25

Taraxaci (aqueous).....................

Root................

3

15

1.

The strength of an extract depends upon the amount of the crude drug it represents. Hence, the smaller the percentage of extract obtained from a drug, the greater the relative strength of the extract, provided that the drug be exhausted with menstrua adapted to secure all the active principles in this form.

The yield of extract is influenced by the character of the menstruum employed. As a general rule, the more aqueous the menstrua, the greater the yield of extract; conversely, the more alcoholic the menstrua, the smaller the yield of extract. To obtain the extracts, therefore, of official strength it is necessary to use official menstrua in the extraction.

Thus the extracts of different drugs are as many times stronger than the drug as the quotient obtained by dividing the drug at 100 by the percentage yield. For example: Podophyllum yields 10 per cent. of extract; then 100 % 10 = 10; that is, the extract is ten times as strong as the drug and the fluid extract, or 0.1 of the extract represents 1 Gm. of the drug or 1 Cc. of the fluid extract. The drug-strengths of the official Extracts, calculated by this method, as well as their relative doses based upon the amounts of drug they represent, are exhibited in the table given on page 109.

The official Extracts are made by extraction with alcoholic menstrua or with water, sometimes by the addition of acid ox alkali.

The Extracts of Cimicifuga, Colocynth, Colocynth Compound, Euonymus, Leptandra, Nux Vomica, Opium, Physostigma, Quassia, and Rhamnus Purshiana, are in powdered form; the others are of pilular consistence.

The Pharmacopoeia gives assay processes for the following extracts: Belladonna Leaves, Colchicum Corm, Hyoscyamus, Nux Vomica, Opium, Physostigma, Scopola, and Stramonium.

Extractum Ferri Pomatum, N. F. - Ferri Malas Crudus (Ferrated Extract of Apples, Ph. Ger.). Extractum Glycyrrhizae Depuratum, N. F. - Succus Liquiritiae, Ph. Ger. (Purified Extract of Liquorice).