210

ELEMENTS OF MATElilA MEDICA.

In this diagram olefiant gas is regarded as a | carbo-hydrogen, etlie-rine as a carbo-hydrogen, and ethereum as f carbo-hydrogen.

Purity. —Absolutely pure ether is not necessary for medicinal pur-poses. Hence in the London Pharmacopoeia we are told that ether whichlias a sp.gr. of 0'750 maybe employed: but it would have been better to havelimited the sp. gr. to 0 - 740. Of course the presence of alcohol or waterincreases the sp. gr. of this liquid: hence the lightest ether is to be pre-ferred, as being the freest from these. Ether which contains no alcoholdoes not coagulate the serum of the blood. Pure ether does not reddenlitmus, but the ether of the shops usually does so slightly. Ten fluid-ounces of water should not dissolve more than one fluidounce of ether,and the solution should be quite transparent.

Physiological Effects, (a) On Vegetables. —Ether , like alcohol,acts as a powerful and rapid poison to plants.

(i b .) On Animals. The effects of it on dogs have been determined byOrfila {Toxicolog. Generale), who found that half an ounce introducedinto the stomach, and the oesophagus tied, caused attempts to vomit,diminished muscular power, insensibility, and death in three hours.Three drachms and a half injected into the cellular tissue of the thighcaused death on the fourth day. Jager (quoted by Wibmer, in Die Wir-kung, &c.) found that half an ounce of ether acted as a fatal poison to acrane : at the end of 48 hours its odour could be readily detected in thebody. He made similar experiments with pigeons and ducks. One ofthe last mentioned animals took altogether an ounce of ether, yet was notdead at the end of 24 hours.

(c.) On man. The operation of ether is analogous to that of alcohol,but is much more rapid and transient. Swallowed in moderate dosesit makes a powerful impression on the mouth, throat, and stomach, allaysspasm, and relieves flatulence : but, according to some observers, it aug-ments neither the heat of the body nor the frequency of the pulse(tSchwilgue, Traite de Mat. Med. 1818) : also, Trousseau and Pidoux,Traitd de Thtrap. 1836). Its first effects on the cerebral functions arethose of an excitant, but the subsequent ones are those of a depressingagent. In somewhat larger doses it produces intoxication like that causedby alcohol. In excessive doses it occasions nausea, a copious flow ofsaliva, giddiness, and stupefaction.

The long and habitual use of ether diminishes the effect of this sub-stance over the system, and therefore the dose must be proportionatelyincreased. Dr. Christison mentions the case of an old gentleman whoconsumed sixteen ounces every eight or ten days, and had been in thehabit of doing so for many years. Yet with the exception of an asthmafor which he took the ether, he enjoyed tolerable health. The chemistBucquet, who died of scirrhus of the colon, with inflammation of thestomach and of the intestines generally, took, before his death, a pint ofether daily to alleviate his excruciating pains (Merat and De Lens, Diet .Mat. Med).

When the vapour of ether, sufficiently diluted with atmospheric air, isinhaled, it causes irritation about the epiglottis, a sensation of fulness inthe head, and a succession of effects analogous to those caused by theprotoxide of nitrogen {vide p. 156), and persons peculiarly susceptible ofthe action of the one are also powerfully affected by the other ( Journ . ofScience, vol. iv. p. 158). If the air be too strongly impregnated with ether,