AND PHARMACOPCEIA. 547 



Compound spirit of ammonia, likewise, is sometimes employed as 

 a menstruum, as in the volatile tincture of guaiacum, and foetid 

 spirit of ammonia. 



TOBACCO. — Nicotiana. This is sometimes given to horses 

 by grooms, for the purpose of keeping their leo-s fine. * 



TOLU, BALSAM OF. See Balsam of Tolu. 



TONICS. Tonics, according to Murray, are those sub- 

 stances whose primary operation is to give strength to the sys- 

 tem. Their operation is not mechanical, as was once conceived; 

 they act not on the simple solids, increasing their tension or tone, 

 but on the living fibre, and are merely powerful stimulants per- 

 manent in their operation. By producing a gradual excitement, 

 they give vigour to the actions of the system ; and as that ex- 

 citement is gradually produced, it is in like manner gradually 

 diminished, and the habitual stimuli continuing to operate, di- 

 minished action does not succeed. Where tonics, however, are 

 given in excess, are used unnecessarily, or for too long a time, 

 they weaken the powers of life. Tonics act primarily on the 

 stomach, the action they excite in that organ being communicated 

 generally by the medium of the nerves to the rest of the system ; 

 some of them, however, are received into the mass of the blood. 

 The immediate effects of a tonic, given in a proper dose, are to 

 Increase the force of the circulation, to augment the animal heat, 

 promote the various seci'etlons, or moderate tliem when morbidly 

 increased, quicken digestion, and render muscular action more 

 easy and vigorous. By some of them these effects are very 

 slowly induced. The affections of the system In which tonics 

 are employed must be obviously those of debility. But pre- 

 viously to their being employed, it is necessary to inquire on 



* A short time since an infusion of about two ounces of tobacco, in a quart 

 of beer, was given to a horse merely for the purpose of keeping his heels fine. 

 He died immediately after taking it. 



I was not present when this circumstance occurred, but am satisfied of the 

 truth of it. I am inclined to believe, however, that there must have been 

 something in this case that was not discovered ; — the stomach may have been 

 previously diseased. I have, within a short period, given an infusion of to- 

 bacco, as well as the tobacco that the infusion had been made from, in the 

 dose of two, three, and four ounces. The only perceptible effect was a 

 shivering, and an appearance which indicated a considerable affection of the 

 stomach, not altogether like nausea, yet approaching towards it; but the 

 effect was transient. According to Boardman, an infusion of three pounds 

 of tobacco has been given without effect. In Bourgelat's " Matiere Medicale 

 Raisonnee," it is said to make an efficacious clyster in obstinate costiveness ; 

 and is prescribed also in chewing balls or masticatories. Muriate of am- 

 monia, dissolved in a decoction of tobacco, is said to be a good remedy for 

 the mange ; rubbing the atfected parts with the fresh leaves of tobacco is 

 said to have the same effect. It is also employed for the mange in sheep and 

 dogs, and in the latter serves to kill fleas and ticks. 



[The smoke of tobacco has been employed as an injection in obstinate con- 

 stipation with good effect. — Ed] 



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