MEDICINES. 39-: 



which the oil of turpentine and laudanum may be administered in cases of 

 cholic. 



Myrrh may be used in the form of tincture, or it may be uiiited to the 

 tincture of aloes as a stimulating and digestive application to wounds. 

 Diluted with an equal quantity of water, it is a good application for canker 

 in the mouth, but as an internal medicine it seems to be inert. 



Nitre. — See Potash. 



Nitrous ^ther, Spirit of, is a very useful medicine in the advanced 

 stages of fever, for while it to a certain degree rouses tlie exhausted powers 

 of the animal, and may be denominated a stimulant, it never brings back 

 the dangerous febrile action which was subsiding. It is given in doses of 

 three or four drachms. 



Oils. — The farrier's list contains many of them, but the scientific prac- 

 titioner has discarded the greater part ; those that are worth retaining will 

 be found under the names of the vegetables from which they are extracted. 



Ointments. — These have been fully described under the accidents and 

 diseases in which their use is required. 



Olives, Oil of. — This is sometimes given as a purgative when aloes 

 or other aperients cannot be obtained. It is useless to give it in a less 

 quantity than a pint, and then it is uncertain in its operation, although 

 harmless. In all liniments and ointments, spermaceti, or even linseed oil, 

 may be substituted without detriment, and the peculiar smell of the latter 

 may be subdued by oil of aniseseed or origanum. 



Opium. — However underrated by some, there is not a more valuable drug 

 on our list. It does not often act as a narcotic except in enormous doses ; 

 but it is a powerful antispasmodic, sedative, and astringent. As an anti- 

 spasmodic, it enters into the cholic drink, and it is the sheet-anchor of the 

 veterinarian in the treatment of tetanus or locked jaw. As a sedative, it 

 relaxes that universal spasm of the muscular system, which is the charac- 

 teristic of tetanus ; and perhaps it is only as a sedative that it has such 

 admirable effect as an astringent; for when the irritation about the mouths 

 of the vessels of the intestines and kidneys is allayed by the opium, undue 

 purging and profuse staling are necessarily arrested. It should, hoAvever, 

 be given with caution. It is its secondary effect which is sedative, and, if 

 given in cases of fever, its primary efiect in increasing the excitation of the 

 frame is marked and injurious. In the earl}' and acute stage of fever, it 

 would be bad practice to give it in the smallest quantity ; but when the 

 fever has passed, or is passing, tliere is nothing which so rapidly subdues 

 the irritability that accompanies extreme weakness ; and it becomes an 

 excellent tonic, because it is a sedative. 



If the blue or green vitriol, or cantharides, have been pushed too far, 

 opium soonest quiets the disorder they have occasioned. It is given in 

 doses of one or two drachms ; either the powdered opium being made into 

 a ball, or the crude opium dissolved in hot water, and given with its sedi- 

 ment. Other medicines are usually combined with it, according to the cir- 

 cumstances of the case. 



Externally, it is useful in opthalmia. In the form of decoction of the 

 poppy head it may constitute the basis of an anodyne poultice ; but it must 

 not !)e given in union with any alkali, with the exception of chalk, in over- 

 Durging ; nor with the superacetate of lead, by which its powers are mate- 

 rially impaired, nor with sulphate of zinc, or copper, or iron. 



From its high price it is much adulterated, and it is rare to meet with it 

 <n a state of purity. The 'best tests are its smell, its taste, its toughness 

 and pliancy, its fawn or brown colour, and its weight, for it is the heaviest 

 jf all the vegetable extracts, except gum arable ; yet its weight is often 



