This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Asphaltus. Jews pitch: a solid, light bituminous substance; of a dusky colour on the outside, and a deep shining black within; of very little taste, and scarcely any smell, un-less heated, in which circumstance it emits a strong pitchy one; not soluble in vinous spirits or in oils; difficultly and only imperfectly melting in the fire; and leaving, on being burnt, a large quantity of ashes. It is said to be found plentifully in the earth in several parts of Egypt, and floating on the surface of the dead sea; at first soft, and growing hard by age.
Abundance of virtues are attributed to this bitumen; resolvent, discutient, sudorific, em-menagogue, and others. It has long, however, been disregarded in this country: the college of Edinburgh has now expunged it from the catalogue of officinals, and that of London retains it only as an ingredient in one of the compositions which complaisance to antiquity has preserved in the shops. Nor is it, among us, to be often met with; its place being generally supplied by different bituminous substances found in France, Germany, and Switzerland, sometimes by the caput mortuum remaining after the distillation of amber, and sometimes by common pitch. Its melting in the fire only partially or not at all, and the quantity of ashes it leaves in burning, distinguish it from these substances, and shew, at the same time, that in its most genuine and perfect state it is a very impure bitumen, mixed largely with earthy matter. Distilled in a retort, it yields, according to Neumann, a little insipid phlegm, and about one eleventh its weight of oil, re-sembling the native petrolea, but of a somewhat more disagreeable empyreumatic smell.
* (a) Spirit has little effect on it. Cullen.