180

ELEMENTS OF MATERIA MEDICA.

acid. Dissolved in water the hydrochlorate of ammonia produces witha solution of nitrate of silver a white precipitate of chloride of silver,recognized by the properties before described (see p. 105): and withchloride of platinum a yellow precipitate {the platino-chloride of ammo-nia) which when collected, dried, and ignited, yields spongy platinum.

Composition. —The following is the composition of this salt:—

Eq.Eq.wt. Percent. Kirwan. Bucholz. Berzel. Vol. Sp.gr.

Ammonia. . . . 1 .

. 17 .

. 31-48 .

. 25 .

. 31 .

. 31-95

Ammoniacal gas 2.0*59027

IIydrochl lc . Acid 1 .

. 37 .

. 68-51 .

. 75 .

. 69 .

. 68-05

Hydrochl ic . Acid gas 2 . 1*28472

Hydrochl te .Amm.l .

. 54 .

. 100-00 .

. 100 .

. 100 .

. 100-00

If one equivalent or two volumes of hydrochloric acidgas be mixed with one equivalent or two volumes ofammoniacal gas, combination is etfected; the gases dis-appear, heat is evolved, and the white hydrochlorate isdeposited.

Analogy would lead us to regard this salt as a chlorideof some metallic base. If such a base exist, it mustconsist of one equivalent nitrogen and four equivalents hydrogen. Berze-lius assumes the existence of this hypothetical metallic base, and calls itammonium, while sal ammoniac is termed by him chloride of ammonium.The protoxide of this suppositious metal will be equal to an equivalentof ammonia and one of water. The advantages of this hypothesis are,that it obviates certain difficulties respecting the compounds formed byammonia with the liydracids, and readily explains the formation of theammoniacal amalgams: its disadvantages are, that it constrains us toadmit the existence of two bodies (ammonium and its protoxide) hithertonot known to exist.

Impurities. —The hydrochlorate of ammonia is sometimes renderedimpure by the presence of chloride of iron. I have met with cakes ofthis salt which when broken presented thin, yellow, concentric laminae iof what I believe to be a double salt of chloride of iron and hydrochlorate |of ammonia. That the chloride of iron performs, in this yellow com-pound, the function of an acid, is shown by its not striking a bluecolour on the addition of the ferrocyanuret of potassium.

Physiological Effects, (a.) On Vegetables. —According to Sir H. iDavy {Agricult. Chemistry), water holding in solution 1-300 of its weightof hydrochlorate of ammonia promotes vegetation. Solutions which con-tained 1-30 of their weight of this salt he found to be injurious.

(A) On Animals. —Courten {Phil. Trans, for 1712), Sprogel, Viborg,and Gaspard (quoted by Wibmer, die Wirkung, &c.), injected solutionsof sal ammoniac into the veins of animals (dogs and horses): large dosesgenerally caused convulsions, sometimes paralysis, and death. From theobservations of Orfila, Smith, Arnold (Wibmer, op. cit.), and Moiroud{Pharmacol. Veter inair e), this salt appears to be a local irritant, and i

when introduced into the stomach in large quantities causes vomiting, Ipurging, and gastro-enteritis. It exercises a specific influence overdistant organs, for the three first of the above-mentioned experimentersobserved that inflammation of the stomach ensued, to whatever part ofthe body the salt might have been applied, and the convulsions andparalysis before referred to, attest its action on the nervous system.Arnold says it diminishes the plasticity of the blood.

(c.) On Man. —Wibmer tried this salt on himself. He took from ten

1 eq.Ammonia= 17

1 eq.

Hydrochl.Acid= 37