This subdivision includes those classes of remedies, whose operation depends entirely upon _mechanical_ principles; and we must agree with Dr. Murray in considering them as the least important of all the articles which we have enumerated, and which cannot therefore constitute objects of elaborate inquiry. ANTHELMINTICS: Remedies which expel worms[234] from the intestinal canal. It has been already stated, (_page 90_) that certain bodies have the power of increasing the peristaltic motions of the intestinal canal, by operating as mechanical stimulants upon its fibres; in this manner the filings of tin and iron, or the irritating down which covers the pods of the _Dolichos Pruriens_, are supposed to act in dislodging and evacuating the worms from the intestines. But there is a variety of remedies employed as vermifuges, which must owe their effects to a very different mode of operation; _Bitters_ for instance appear to prove an absolute poison[235] to these animals, while they, at the same time, give an increased tone to the organs of digestion; from whose debility the generation of worms would seem to arise. Other remedies, again, obviously depend upon their simple cathartic property, for the powers which they possess in the evacuation of worms. See _Terebinthinæ Oleum_—_Cambogia_. In the cure of Ascarides the local application of the remedy becomes necessary, in the form of glyster, and which acts both _mechanically_ in washing out the gut, and _medicinally_ in proving obnoxious to the animals. According to the experience of some of our best practitioners, a strong decoction of the _Semina Santonici_ proves most efficacious upon these occasions. DEMULCENTS: Medicines which are capable of shielding sensible surfaces from the action of acrid matter, by involving it in a mild and viscid medium.