^79 ANALYSIS OF THE 



for these, therefore, various hypotheses have been proposed. 

 The observation has been urged, which, to a certain extent, is 

 undoubtedly just, that substances given in small doses in a 

 state of great dilution, inay, from this dilution, produce more 

 effect on the general system, than the quantity given would 

 lead us to expect. The temperature of the water, too, it has 

 been supposed, may have a considerable share in aiding the ef- 

 fect ; and these two circumstances in particular, it has been 

 imagined, may favour the action of the iron. This is the view 

 of the subject given by Dr Saunders, in his Treatise on Mine- 

 ral Waters. Some of the other ingredients, too, it has been 

 supposed, may exert unknown powers. Thus, some effect has 

 been ascribed to the agency of the nitrogen gas which rises 

 through the water. And Dr Saunders himself, apparently 

 not very well satisfied with the reasoning he had employed, 

 allows some weight to the opinion suggested by Dr Gibbes, 

 that the siliceous earth assists in the general effect of the Bath 

 waters ; — remarking, that though there is only a grain of it in 

 half a pint of the water, this forms no objection, when the 

 great powers of very minute quantities of active substances are 

 considered ; that neither is its insolubility in the animal fluids 

 an objection, as it exists in the water in a state of solution ; 

 and that though it has neither taste nor smell, it may be an 

 active substance, since there are indisputably powerful medi- 

 cines, which have little of either of these qualities. 



All this, it is superfluous to observe, is extremely unsatisfac- 

 tory. With regard to the iron, the only active substance, — al- 

 lowing full weight to the observations, that small quantities of 

 active medicines, under great dilution, operate with increased 

 power, and that a high tempeiature may aid their operation on 

 the stomach, — still we cannot believe that one-sixtieth of a grain, 

 the quantity in a pint of this water, can produce any import- 

 ant 



