MATERIA MEDICA. 



thorough change in the fluids of the body, 

 when morbidly vitiated. 



These uses may be illustrated from 

 practical observations in cases of tooth- 

 ach, angina, dropsy, and siphilis. 



The cautions to be observed in the em- 

 ployment of sialagogues, as derived from 

 their nature, respect chiefly the stimulus 

 they occasion to the salivary glands and 

 neighbouring parts ; the time required 

 by the order of interna for the produc- 

 tion of evacuation ; the difficulty, per- 

 haps, in some cases, the impossibility, of 

 exciting salivation by means of the inter- 

 na; and the debility induced in the sys- 

 tem from excessive evacuation. The 

 conditions of the system chiefly requir- 

 ing attention in their employment, are, 

 old age, constitutions habituated to siala- 

 gogues ; peculiarities in constitution, de- 

 termining the mercury to act on other 

 parts than the salivary glands ; menstrua- 

 tion ; and pregnancy. Sialagogues are 

 contra-indicated, where there is an un- 

 common determination to the salivary 

 glands; preternatural sensibility in them; 

 deficient serosity ; and general debility of 

 the system. 



9. Of Emollients. 



By emollients are meant medicines 

 which have a power of relaxing the 

 living animal fibre, independently of me- 

 chanical action ; they render the part to 

 which they are immediately applied 

 more soft and flexible than it was be- 

 fore. They excite a peculiar sensation 

 indistinctly referred to the part to which 

 they are applied; they produce through 

 the rest of the system an effect, in some 

 degree analogous to that taking place in 

 the part on which they more immediately 

 act. The changes induced in the system 

 from the primary effects of emollients 

 are, a dimunition of the power of cohe- 

 sion in various parts of the animal body; 

 a diminution of the tonic power in the 

 system ; an increase of the capacity of 

 containing vessels in the part on which 

 they more particularly act, and in some 

 degree in the system in general; and an 

 increase of irritability and sensibility 

 through the entire frame. 



They may be regarded as humectant, 

 of which we have examples in warm wa- 

 ter, warm vapour, and warm baths ; 

 laxative, as marshmallows, mallows, white 

 lily root ; lubricative, as bland oils, suet, 

 hog's lard ; atonic, as opium, foot-bath. 



The curative indications of emollients 

 may be collected -hence : 1, From their 



producing a change in the state of the 

 moving solids. Hence they may be em- 

 ployed to restore the natural flexibility to 

 parts morbidly rigid ; to diminish a mor- 

 bid increase of tonic power. 2. From 

 their producing a change in the state of 

 the containing vessels. Hence the}' may 

 be employed, to obviate the effects of 

 morbid distention ; to remove obstruc- 

 tions. These indications may be illus- 

 trated and confirmed, from practical ob- 

 servations concerning the effects of this 

 class of medicines, as employed in cases 

 of contraction, rigidity, and tumor. The 

 cautions to be observed in the employ- 

 ment of emollients, as derived from their 

 nature, chiefly respect their influence as 

 acting on the system in general ; and the 

 effects of a degree of laxity induced in 

 particular parts, higher than is natural 

 to these. The conditions of the system 

 which chiefly require attention in their 

 employment are, the period of youth ; 

 delicacy of habit; and debility. The 

 circumstances chiefly to be attended to 

 in the necessary re'gimen, respect the 

 temperature and air in which the patient 

 is kept ; and the mode of applying the 

 emollient. The class of emollients are 

 chiefly contra-indicated by the presence 

 of the following morbid states : a high de- 

 gree of morbid relaxation in the system 

 in general ; and a peculiar sensibility of 

 the moving fibres. 



10. Of Refrigerants. 



These are medicines which, as their 

 name implies, are supposed to diminish 

 the heat of the living body, not by the 

 application of an actual cold, but by a 

 power peculiar to themselves. 



They may be considered under the 

 two divisions of acids or acetous fruits, as 

 tamarinds, berberries, lemons, wood-sor- 

 rel ; and neutral salts, as nitre, Glauber's 

 salt, sal polychrest. They may hence be 

 usefully employed ; 1. In cases of febrile 

 heat, or of general plethora, and an use- 

 ful auxiliary to the tribe of refrigerant 

 cathartics. 2. As sedatives, to diminish 

 undue irritability and action of any of the 

 vascular systems, and are hence usefully 

 conjoined with the sedatives, more pro- 

 perly so called, of Class XV. of this sys- 

 tem. In the employment of these medi- 

 cines attention should be paid to their 

 power of diminishing action, and either 

 generally checking the secretions of 

 the system, or augmenting some by a 

 diminution of others. Hence they are 

 contra-indicated in cases of chlorosis, 



