156

ELEMENTS OF MATERIA MEDICA.

Prot. Nitr.

Its equivalent, by weight, is 22, by volume 1. Its sp. gr.according to Dr. T. Thomson, is T5277. When subjected toa pressure of 50 atmospheres, at 45° F., it is condensed into alimpid colourless liquid.

Characteristics.—-T he only gas with which it is possible to confoundit, is oxygen, with which it agrees in being colourless, not combustible,Before combustion. After combustion. but a powerful Supporter of Combustion,

re-inflaming a glowing match. It maybe readily distinguished by mixing itwith an equal volume of hydrogen, andexploding it by the electric spark, bywhich we obtain one volume of nitrogen and an equivalent or 9 parts ofwater.

Composition. —It consists of one equivalent or 14 parts of nitrogen,and one equivalent or 8 parts of oxygen ; or, by measure, a volume of ni-trogen and half a volume of oxygen condensed into the space of a volume.

1 eq.Protox.Nitr.

1 eq.Hydrog.

1 eq.Nitrog.

= 22

= 1

= 14

and l eq.Water=9.

Eq.

Nitrogen.1 .

Oxygen ..... 1 .

Eq.Wt.

. . 14 .

. . 8 .

Per Cent.

. . 63-6 . .

. . 36-4 . .

Davy.

. 63*3

.m

Vol.

Nitrogen gas ... 1Oxygen gas. . . . 0'5 .

Sp. gr-. 0-9/22• 0-5555

Protoxide Nitrogen ] .

. . 22 .

. .100-0 . .

. 100

Protox. Nitrogen gas 1

. 1-5277

Physiological effects, (a.) On vegetables. —Germinating seeds (peas)when watered with a solution of this gas seemed unaffected by it. Plantsintroduced into vessels filled with the gas mostly faded in about threedays, and died shortly after. (Davy’s Researches.) But Drs. Turner andCliristison did not find that it was injurious to vegetation. (Christison,On Poisons, p. 756).

{b.) On animals. —The effects of this gas on insects, annelides, mol-lusca, ampliibials, birds, and mammals, were examined by Sir II. Davy.On all it acted as a positive poison. It produced “ peculiar changes in theirblood and in their organs, first connected with increased living action ;but terminating in death.” (Davy, p. 449). Slowly injected into theveins of animals, considerable quantities were found by Nysten to pro-duce slight staggering only ; larger quantities produced* the same disor-der of the nervous system noticed when the gas is respired. ( Recherches,p. 77 and 78).

(c.) On man. —When inhaled its effects on the nervous system are mostremarkable : I have administered this gas to about one hundred persons,and have observed that after the respiration of it from a bladder for a fewseconds, it usually causes frequent and deep inspirations, blueness of thelips and countenance, an indisposition to part with the inhaling tube,and a temporary delirium, which subsides in the course of three or fourminutes. The sensations are usually pleasing. The delirium manifestsitself differently in different individuals, as in some by dancing, in othersby fighting, &c. In some few cases I have seen stupor produced. Sing-ing in the ears, giddiness, and tingling sensations in the hands and feet,are sometimes experienced.

Uses. —It has been employed in some few cases only of disease. Bed-does used it in paralysis with benefit; but found it injurious to the hyste-rical and exquisitely sensible. (Davy’s Researches, p. 542). In a remark-able case of spasmodic asthma, related by Mr. Curtis ( Lancet, vol. ii. for1828 and 1829), it acted beneficially. In a second case it also gave relief.