PHYSIOLOGICAL CLASSES OF MEDICINES.

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which produce an increased discharge of nasal mucus. When theyexcite sneezing they are called sternutatories (sternutatoria) or ptarmics(from 7rrat'pw, I sneeze ).

Most foreign matters applied to the pituitary membrane promote thesecretion of nasal mucus. Sugar and the labiate plants operate mildly;euphorbium and white hellebore with great violence. Some kinds ofsnuff will, in persons unaccustomed to their use, affect the generalsystem, giving rise to nausea, giddiness, great depression of muscularpower, and slight disorder of the mental functions—effects which I havepersonally experienced on two or three occasions. The continuedemployment of snuff injures the sense of smell and alters the tone of thevoice. In syphilitic affections of the nose, and where there is a disposi-tion to nasal polypus, the continued use of errliines may perhaps beinjurious. Errliines have been principally employed to relieve chronicaffections of the eyes, face, and brain ; for example, chronic ophthalmia,amaurosis, headache, &c. They can only be useful on the principle ofcounter-irritation.

Scliwilgue enumerates the following pmposes for which sneezing isexcited : to excite respiration when this function is suspended ; to pro-mote the expulsion of foreign bodies accidentally introduced into the air-passages ; to occasion a general shock at the commencement of dangerousdiseases which we wish at once to suppress; to augment the secretion ofnasal mucus, and of tears; to favour the excretion of mucus collectedin the nasal sinuses ; to rouse the action of the encephalon, of the senses,of the uterus, &c., and to stop a convulsive or spasmodic state of therespiratory apparatus. We should not, however, forget that the con-cussion occasioned by sneezing is not always free from dangerousresults, especially in plethoric habits, and persons disposed to apoplexy,or affected with hernia, prolapsus of the uterus, &c.

3. Sialogogues ( sialogoga , or sialagoga, from aiaXov, the saliva, anday o), to convey or drive out ) are medicines which excite the salivarydischarge. They are of two kinds, local and remote.

a. Local sialogogues. —These are sialogogues which are applied to themouth. When used in a soft or solid state they are called niasticato-ries (masticatoria , from mastico, to eat or chew). They act on themucous follicles of the mouth and the salivary glands. Most solid orsoft bodies, when chewed, increase the flow of saliva; thus wax andmastic produce this effect. Acrids, however, as horse-radish, mezereon,pellitory of Spain , and ginger, possess this property in an eminentdegree.

In almost all parts of the world masticatories are more or lessused. In the East Indies betel-nuts (the seeds of Areca Catechu) arechewed, with quick lime and the betel-leaf (the leaf of Piper Betel).The Indians have a notion that these substances fasten the teeth, cleanthe gums, and cool the mouth ( Ainslie’s Materia Indica). In this countrythe masticatory commonly employed by sailors is tobacco.

As the saliva is generally swallowed, masticatories do not confinetheir action to the mouth, but excite likewise the stomach. Peron( Voyage aux Terres Australes) was convinced that he preserved hishealth, during a long and difficult voyage, by the habitual use of thebetel; while his companions, who did not use it, died mostly of dysentery.Eor habitual use, and as mere sialogogues, mucilaginous and emollient