NATURE OF MEDICINES. 541 



from the action of acrid matters, as poultices and fomentations. Demulcents also come under the 

 same heading. These are given internally, and produce their effects on distant organs through the 

 circulation gum acacia for example, gruel, barley-water, liquorice extract, &c. 



Epispastics. Medicaments which, applied to the skin, produce temporary inflammation 

 irritation, or vesication. They are called also vesicants, rubcfacients, blisters, and counter-irritants. 

 They are a most useful class of remedies when skilfully applied. Their uses are many, (i) they 

 relieve inflammation of internal organs by drawing the blood to the surface. (2) Blisters may be 

 used as general stimulants in some low forms of fever. But they are not to be used in 

 inflammatory diseases, until the general excitement has been subdued by other means. (3) They 

 are useful in dropsy of the pericardium, pleura, &c., in that they remove serum from the blood. 

 (4) They are sometimes used to denude the skin, in order to introduce some medicine, such as 

 morphia or strychnine, quickly into the blood by absorption. Before applying a blister to the 

 dog, cut off closely or shave the hair from the part. Strong solution of ammonia is a good 

 blister, applied by means of a woollen rag, covered over with oiled silk. It does its work quickly 

 and well, and is to be preferred to cantharides if there is anything the matter with the urinary 

 organs. 



A slower and milder blister is the Emplastrum Cantharidis of the Pharmacopoeia. It has to 

 be kept on, however, for ten or twelve hours, and this with the dog cannot always be conveniently 

 done. If it be tried, however, it must be covered well up, and the dog muzzled. A quicker 

 and most effective cantharidine blister is the Liquor Epispasticus of the shops. The skin is to be 

 painted with it four or five times if necessary. Then, as a rubefacient, we have turpentine poured 

 over a piece of flannel, wrung out of very hot water, and applied to the skin. After a blister 

 well rises, tap it, and dress with simple ointment. 



Narcotics, including also Anodynes, and the so-called Hypnotics and Soporifics, ease pain, 

 and also produce sleep. Those chiefly used in dog practice are Belladonna, Hyoscyamus, and 

 Opium. Great caution is to be observed in their administration. 



Sedatives must, as a rule, also be cautiously handled. They are in their nature calmatives 

 to the system. They are employed in diseases where we have much nervous or vascular 

 excitement, and the doses given must be in proportion to the degree of excitement. Under 

 the same heading we include anastlietics, those medicines the vapour of which, if inhaled, 

 produces insensibility. 



Stimulants are medicines which increase, though not permanently, the vital functions, and 

 this is always followed by a corresponding depression. When given, therefore, in debility or 

 exhaustion, the dose must be frequently repeated, until the body regains strength enough to be 

 able to do without the stimulants. 



Tonics. Medicines which, given for some length of time, strengthen the vitality without 

 producing any apparent excitement. If a horse on a journey becomes tired, he can be urged 

 on either by applying the whip to him, or by stopping and giving him a feed of oats. The whip 

 represents the stimulant, the oats the tonic. Now these remedies, although very powerful for 

 good when judiciously administered, are just as powerful for evil when unskilfully prescribed. 

 They are most useful in debility, and in cases where there is a want of tone in the secreting 

 organs. They should, however, never be used when there is the least tendency to inflammation, 

 or even irritation of the digestive canal, or when the secretions are vitiated. Before giving a 

 dog a course of tonics, it is better to give some mild aperient, and one occasionally during the 

 course. Quinine and arsenic are not only tonics, but they also counteract periodical fever, and 

 are hence sometimes called Febrifuges. 



