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ELEMENTS OF MATERIA MEDICA.

having employed glass jars of too small size. We have good evidence ofthe poisonous operation of this gas on vegetables in the neighbourhoodof those chemical manufactories in which carbonate of soda is procuredfrom common salt. The fumes of the acid which issue from these workshave proved so destructive to the surrounding vegetation, that in someinstances the proprietors have subjected themselves to actions at law,and have been compelled either to pay damages, or to purchase the landin their immediate neighbourhood.

(b.) On animals this gas acts injuriously, even when mixed with 1500times its volume of atmospheric air. Mice or birds introduced into thepure gas struggle, gasp, and die, within two or three minutes, Dilutedwith atmospheric air, the effects are of course milder, and in a ratio tothe quantity of air present. In horses it excites cough and difficulty ofbreathing. When animals are confined in the dilute gas, in addition tothe laborious and quickened respiration, convulsions occur before death.Messrs. Rogerson state, that “ in a legal suit for a general nuisance,tried at the Kirkdale Sessions-house, Liverpool , it was proved that horses,cattle, and men, in passing an alkali-works, were made, by inhaling thisgas, to cough, and to have their breathing much affected. In the caseof Whitehouse v. Stevenson, for a special nuisance, lately tried at theStaffordshire assizes, it was proved that the muriatic acid gas from asoap manufactory destroyed vegetation, and that passengers were seizedwith a violent sneezing, coughing, and occasional vomiting. One witnessstated, that when he was driving a plough, and saw the fog, he wasobliged to let the horses loose, when they would gallop away till theygot clear of it.” It acts as an irritant on all the mucous membranes.

(c.) On man this gas acts as an irritant poison, causing difficult respira-tion, cough, and sense of suffocation. In Mr. Rogerson’s case, it causedalso swelling and inflammation of the throat. Both in man and animalsit has appeared to produce sleep.

The action of hydrochloric acid gas on the lungs is injurious in at leasttwo ways: by excluding atmospheric air, it prevents the decarbonizationof the blood; and, secondly, by its irritant, and perhaps also by itschemical properties, it alters the physical condition of the bronchialmembrane. The first effect of attempting to inspire the pure gas seemsto be a spasmodic closure of the glottis. Applied to the conjunctiva, itcauses irritation and opacity.

Use. —It has been employed as a disinfectant, but is admitted on allhands to be much inferior to chlorine. The Messrs. Rogerson deny thatit possesses any disinfecting property. It is perhaps equally difficult toprove or disprove its powers in this respect. The experiments of Guyton-Morveau, in purifying the cathedral of Dijon , in 1773, are usually referredto in proof of its disinfecting property. If it possess powers of thiskind, they are certainly inferior to chlorine, or the chlorides of lime orsoda; but, in the absence of these, hydrochloric acid gas may be tried.In neutralizing the vapour of ammonia it is certainly powerful.

Application.— In order to fumigate a room, building, or vessel, withthis gas, pour some strong sulphuric acid over dried common salt, placedin a glass capsule or iron or earthen pot, heated by a charcoal fire.

Antidote. —Inhalations of the vapour of ammonia may be serviceablein neutralizing hydrochloric acid gas. Symptoms of bronchial inflamma-tion are of course to be treated in the usual way.