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ELEMENTS 01' MATERIA MEDICA.

sulpliuret is formed, and the fibrin is dissolved : the compound of fibrinand potash thus formed may be termed fibrate of potash. The additionof an acid precipitates the fibrin somewhat altered in its properties, andcombined with some of the precipitant. The same kind of effect is pro-duced by the action of potash on albumen: thus, this substance uniteswith the alkalies to form soluble compounds, which may be termedalbuminates. Gelatine is also readily dissolved by alkalies, with thedeposition of any phosphate of lime which it may contain. These phe-homena are to a certain extent comparable to those of saponification. Itappears, therefore, that the caustic alkalies form soluble compounds withsubstances which enter largely into the composition of the organizedtissues. Hence the observation of Orfila, that alkalies are of all corrosivepoisons those which most frequently perforate the stomach, is readilyaccounted for; for the intestinal mucus readily dissolves in alkalies,Whereas it is coagulated by acids; so that the former are much morequickly brought in contact with the living tissues. These resist, for acertain time, the chemical influence of the caustics, but the affinitiesbeing powerful, the vital properties soon cease to offer opposition—thepart dies, and then the alkalies commence their chemical action on thetissues, which they speedily dissolve. Hence, if a large quantity ofpotash be ' swallowed, the most violent symptoms are observed, thoughthey are of the same general kind as when the mineral acids have beentaken.

When liquor potassae is taken in small doses, and properly diluted, itsaturates the free acids contained in the stomach, and which the recentinvestigations of physiologists have shown to be so essential to the diges-tive functions. Hence the continued use of alkalies must be always inju-rious, since they disorder the assimilative process by altering the chemi-cal properties of the healthy ventricular secretion.

If the quantity of potash swallowed be more than sufficient to neu-tralize the free hydrochloric acid, but insufficient to have any chemicalaction on the living tissues, it acts as a slight irritant, increases the secre-tions of the alimentary canal, becomes absorbed, and alters the qualitiesof the secreted fluids, more particularly those of the mine. Moreover,the modification thus produced in the quality of the renal secretion isaccompanied by an increase in the quantity, so that the alkalies rankamong our most powerful diuretics—an effect which may be in partowing to the local stimulus which they communicate to the secretingVessels in their passage through them.

By continued use the alkalies give rise to increased activity of thedifferent secreting organs, and of the absorbing vessels and glands;effects which are analogous to those caused by mercury. After some timethe digestive function becomes disordered, the appetite fails, the bloodbecomes thinner and darker coloured, and loses its power of spontaneouscoagulation when drawn from the body; the whole system, and more par-ticularly the digestive organs, become enfeebled; and a state preciselysimilar to that of scurvy is brought on. It is said if the alkalies betemporarily suspended the blood speedily re-acquires its coagulability,but loses it again when we resume their employment. These phenomenadeserve especial notice, as being precisely analogous to those of scurvy—a disease which has been usually supposed to be brought on by the use