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Broadly categorizing, there are actually three kinds of oil. In addition to the aromatic essential oils and the vegetable- and animal-derived fixed oils there are the mineral oils (and paraffin wax). Mineral oils are a mixture of liquid hydrocarbons obtained from petroleum, and they may be highly volatile or non-volatile.

Fixed oils are obtained from both the vegetable and the animal kingdom and are often called fatty oils, as chemically they are fats. They are more or less smooth and greasy to the touch, and leave a permanent grease spot when in liquid condition and dropped on paper. They vary greatly in their point of congelation, olive oil becoming solid at a little above 32° F., whereas flaxseed oil can remain fluid at 4° below zero. Pure fixed oils have little taste or smell. They are lighter than water, and they do not evaporate easily; however, they do boil at about 600° F. and at this temperature are converted into vapor. Heated in open air, especially with the aid of a wick, fixed oils do take fire and burn with a bright and sooty flame. These oils are insoluble in water, but are capable of being mixed with water by the assistance of a mucilage, forming mixtures which are called emulsions (see Chapter Nineteen, “Lotions & Creams”). Fixed oils comprise most of the oils in common use such as Olive, Almond, Sesame, cod liver, and Castor oil (and mineral oils).

It is not commonly realized that fixed oils, especially when used as warm/hot infusions and decoctions, are good solvents for abstracting resins, oleo-resins, essential oils, and flavonoids.

Chemically, in most cases, fixed oils consist primarily of three substances which are considered the three elementary parts of fat: olein, stearin, and palmitin. Olein is the liquid portion of fat, and stearin and palmitin are both solid portions; hence, the consistency of fixed oils and fats is due to the relative proportion of these substances. Thus, Almond oil, being composed principally of olein, is always liquid at ordinary temperatures, while butter, tallow, and lard, being largely stearin, are solid. Fixed oils are decomposed in the intestine by the digestive juices into fatty acids and glycerin and sometimes monoglycerides.

If you are so inclined, do not let these lists of plant constituents overwhelm you or put you off. They are important only when you care about them, and they are equally unimportant if you don’t care. So, I include them in our discussions for the benefit of those individuals who are interested. Feel free to ignore them, for they are specialized information, not crucial information. Later, if you decide to focus on them for any purpose, they are here for you as a reference.

Decomposition and the resulting rancidity of fats and oils are due to exposure to heat, air, moisture, and/or light. This change is believed due to the presence of animal and vegetable tissue, protein, and other albuminous or mucilaginous compound substances which cause fermentation, induce decomposition, liberate the fatty acids, and produce volatile, odorous acids. Rancidity is noticeable by the oil giving a sharp, unpleasant taste and odor. The presence of water in a fatty oil favors the production of rancidity.

While you select and prepare your menstrua, keep in mind, regardless of which solvent or combination of solvents you choose, the “emptier” a solvent is, the more effective it will be as an extractant. In other words, a solvent that is not already floating a bunch of dissolved minerals within its liquid volume obviously has more room within itself to dissolve and hold the components of an herb that has been mixed with it. Likewise, once a solvent has dissolved components of the herb and brought them into solution, it is no longer as active because in this state it is more saturated and less hungry (although it might now dissolve components it couldn’t when it was pure). Therefore, for example, soft water (which by definition is empty of dissolved mineral content—that’s why it’s still