MINERAL WATERS OF DUNBLANE. 461 



The proportion of iron I have stated as similar to that of the 

 North Spring, from the colour produced by the tincture of 

 galls being nearly the same. 



From the almost perfect similarity in the composition of 

 the two waters, with regard to the proportions of their ingre- 

 dients, there is every reason to conclude, that they are from 

 the same spring ; the weaker being either mixed with surface 

 water at the pool, or being diluted in its course. 



The determination of the composition of this water, suggests 

 the question, whether this is such as to account for the medi- 

 cinal effects it produces. It acts, as has been stated, as a diu- 

 retic, and in a larger dose, as a cathartic. This water, and the 

 mineral water of Pitcaithly, present, in some respects, a pecu- 

 liarity. The greater number of saline waters which have a 

 purgative quality, contain magnesian salts, to which, as they 

 are known to act as cathartics, the effect is obviously to be as- 

 cribed. Of the ingredients of the Dunblane and Pitcaithly 

 Springs, muriate of lime is scarcely known to have any purga- 

 tive power in its pure form, and if muriate of soda possess it, 

 it is only in an inconsiderable degree. Still, there can be no 

 doubt, that it is to this impregnation that their operation is 

 owing, and they afford a proof, therefore, of what is indeed 

 sufficiently established, that the powers of mineral waters are 

 often much greater than could be expected from the nature 

 and quantity of their ingredients, and that the action of saline 

 substances is increased, and considerably modified, when they 

 are in a state of great dilution. 



Independent of its purgative operation, and its adaptation to 

 the treatment of diseases in which this is advantageous, its 

 composition may probably render it a remedy of efficacy in 

 some constitutional affections, particularly in scrofula. Mu- 

 riate of lime has attained some celebrity in the treatment of 



Vol. VII. P. IL 3 N this 



