"Oils are liquid or solid substances, unctuous to the touch, and characterized by inflammability and the property of leaving a greasy stain upon paper." They may be arranged in two classes, Fixed and Volatile, depending on their behavior on the application of heat.

The more important Fixed Oils are:

Oleum Olivae, Olive Oil, obtained from the ripe fruit of Olea europea (Fam. Olea-cece), native of Eurasia. It is used as a nutritive in adults, and as a mild laxative (dose, 5 to 20 mils) in infants.

Oleum Ricini, Castor Oil, derived from the seeds of Ricinus communis, (Fam. Euphorbiacece), native of India. It is used as a purgative in fermentative diarrheas, cholera morbus, and acute constipation. Dose, 15 mils.

Oleum Tiglii, Croton Oil, obtained from the seeds of Croton tiglii (Fam. Euphorbiacece), native of India and the Philippines. It is used with great caution as a prompt, powerful, drastic purge for a depletant in cerebral congestions, and to assist in overcoming acute obstipation. Dose, 0.05 mil in olive oil.

Less important official Fixed Oils are:

Oleum Amygdalae Expressum, Oleum Sesami, Oleum Theobromatis (all used as emollients); Oleum Gossypii Seminis, (a demulcent and common substitute for olive oil); Oleum Lini (used to prepare "Carron Oil"); and Oleum Morrhuae (a discarded treatment for tuberculosis).

Adeps, Adeps Lanae, Cera Flava, or beeswax, and Cetaceum, or spermaceti, are otber forms of official fixed oils.

The Volatile Oils are all liquid preparations, usually obtained by distilling the flowers, seeds, fruits, leaves, or bark of odoriferous plants. These oils may best be classified according to the predominating chemical constituent.

Group I. - Oils in which terpenes predominate:

Oleum Aurantii, Oil of Sweet Orange, expressed from the fresh peel of Citrus Aurantium sinensis (Fam. Rutacece). Used as a flavoring agent in preparing Spiritus Aurantii Compositus.

Oleum Terebinthinae Rectificatum, Rectified "Spirits of Turpentine," a purified distillate from the oleoresin of Pinus palustris and other species of Pinacece. Used externally as a rubefacient, and internally as a carminative in doses of 0.3 mil.

Group II. - Oils in which alcohols and their esters predominate:

Oleum Coriandri, Oil of Coriander, distilled from the ripe fruit of Coriandrum sativum (Fam. Umbelliferce) native of Italy. A mild carminative; also a flavoring agent used in Syrupus Sennce.

Oleum Lavandulae, Oil of Lavender, distilled from the fresh flowers of Lavandula vera (Fam. Labiatce), native of South Europe. A carminative; also a flavor for Tinc-tura Lavandulae Composita.

Group III. - Oils in which aldehydes predominate:

Oleum Cassiae, Oil of Cinnamon, a rectified oil distilled from Cinnamomum Cassia (Fam. Lauracece), growing in Ceylon. Used as a carminative; also a flavor in Aqua Cinnamomi and Spiritus Cinnamomi.

Oleum Limonis, Oil of Lemon, expressed from the fresh peel of ripe Citrus medica Limonum (Fam. Rutacece). Used for flavoring.

Group IV. - Oils in which a ketone predominates:

Oleum Menthae Piperitae, Oil of Peppermint, distilled from the dried leaves and flowering tops of Mentha piperita (Fam. Labiates), a perennial plant of Eurasia and North America. Used as a carminative; also as a flavor in Aqua Menthae Piperitae, and in Spiritus Menthae Piperitae.

Group V. - Oils in which aromatic acids and esters predominate:

Oleum Gaultheriae, and Oleum Betulae; see Methylis Salicylas, page 33.

Group VI. - Oils in which phenols or their esters predominate:

Oleum Anisi, Oil of Star Anise, distilled from the ripe fruit of Pimpinella Anisum (Fam. Umbelliferce), a plant of Russia. Used as a flavoring agent in Tinctura Opii Camphorata.

Other less important official volatile oils are:

Oleum

Amygdalae Amarae

Group

III

Formerly used for its HCN content

"

Cajuputi

,,

*VII

Formerly used as a carminative

"

Cari

,,

I

A flavor in Spir. Juniperi Comp.

"

Caryophylli

,,

VI

A flavor; used also in poultices

"

Chenopodii

,,

*VII

A vermifuge for the round-worm

"

Cubebae

,,

I

A discarded urinary antiseptic

"

Eucalypti

,,

*VII

A mild nasal antiseptic

"

Foeniculi

,,

VI

A discarded carminative

"

Menthae Viridis

,,

IV

A substitute for peppermint oil

"

Myristicae

,,

I

Used in "spice" poultice

"

Picis Liquidae Rect.

,,

I

Formerly used in tuberculosis

"

Pimentae

,,

VI

A savor

"

Pini Pumilionis

,,

II

Used empirically for bronchitis

"

Rosmarini

,,

II

Will drive away flies

"

Santali

,,

II

Formerly used in G.-U. treatment

"

Sassafras

,,

VI

A flavor

"

Sinapis Volatile

,,

•VIII

A vesicating counterirritant

"

Terebinthinae

,,

I

For making the rectified "spirits"

"

Thymi

,,

*VII

A flavoring agent

* See U. S. Dispensatory.

Properties of the Oils:

Color

Odor

Taste

Sol. C2H5OH

Dose

Oleum Olivae

Slight

30 mils

Oleum Ricini

Misc.

15 mils

Oleum Tiglii

Do not

Slight

0.05 mils

Oleum Gossypii Sem.

Slight

30 mils

Oleum Morrhuae

Slight

10 mils

Oleum Aurantii

1 in 7

0.2 mil

Oleum Anisi

1 in 3

0.2 mil

Oleum Cassiae

1 in 3

0.2 mil

Oleum Coriandri

1 in 3

0.2 mil

Oleum Lavandulae

1 in 3

0.2 mil

Oleum Limonis

0.2 mil

Oleum Menthae Piper.

1 in 4

0.2 mil

Oleum Terebin. Rect.

1 in 5

0.3 mil

Papaver Somniferum

Papaver Somniferum.