This man had formerly been a shoemaker. There was no evidence as to the period at which he swallowed these hairs; but, from the derangement which always existed in the bowels, and the pain referred to the sigmoid flexure, little doubt can be entertained but that these hairs were the cause of all his complaints, and ultimately of his death.” CL. II. ASTRINGENT POISONS. LEAD. This metal appears to have been known in the earliest ages; and is mentioned several times by _Moses_.[346] It has a bluish-white colour; is very brilliant when first cut with a knife, but soon tarnishes by exposure to air; when rubbed violently, it emits a peculiar smell; it is malleable and ductile, but possesses very little tenacity. It is scarcely sonorous; being the softest of all the metals, it yields readily to the hammer. Its specific gravity is 11·35; it melts at 612°. According to the experiments of _Dr. Thomson_,[347] it is susceptible of four degrees of oxidation, presenting us with four distinct, and well defined oxides, viz. Yellow (_protoxide_) contains of lead 91·5 oxygen 8·5 Yellow (_deutoxide_) contains of lead 90·5 oxygen 9·5 Red (_tritoxide_) contains of lead 88· oxygen 12· Brown (_peroxide_) contains of lead 80· oxygen 20· Lead, in its metallic state, does not exert any action on the living system; but, when oxidized, or in the state of salt, its virulence is very considerable, producing a train of symptoms, so peculiar to itself, as to justify our placing its preparations in a separate class, under the title of _astringent_ poisons, as explained at page 202. Metallic lead, although _per se_ inert, may occasion deleterious effects when introduced into the stomach, in consequence of its meeting with acids in the _primæ viæ_; from the same cause, liquids which are liable to become in any degree acidulous, if kept in leaden vessels, may be productive of much danger to those who drink them. Pure water, provided the air be excluded, does not appear to exert any sensible action upon this metal; but the combined influence of these agents converts the lead into a carbonate: a fact which is at once exemplified by the white line which is so constantly visible at the surface of the water preserved in leaden vessels. So well acquainted were the ancients with this fact, that we find frequent allusions in their works to the dangerous property of leaden utensils. _Vitruvius_[348] published a very strong remonstrance against leaden pipes, when used for the purpose of conveying water; and _Galen_ cautions us continually, not to employ water that has flowed through pipes of this metal; since he had observed that the _sediment_ of such water, (υποσταθμη του τουιουτου υδατος) rendered such as swallowed it, δυσεντερικους, subject to disorders in the intestines.