602 PRACTICE OF PHYSIC. 



tern. But this seems to be almost peculiar to this substance, 

 that, given even in moderate quantity, it very readily passes to 

 the kidneys ; and from circumstances which we cannot explain, 

 it seems to be there united with a certain portion of the urine 

 only ; and being thus in a concentrated state when carried on 

 to the bladder, it gives a considerable irritation and inflam- 

 mation to the neck of it, in consequence of which a frequent 

 stimulus to the voiding of urine, and a painful difficulty in the 

 voiding of it ; symptoms very well known to every medical 

 man, under the title of Strangury, are produced. 



" In explaining this very peculiar effect of cantharides I have 

 insinuated a theory of their being united with a certain portion 

 of the urine only, and of their being thereby in a more concen- 

 trated state, which will not perhaps appear clear to every body ; 

 but that there is a foundation for such reasoning appears to me 

 very strongly from hence, that the effects mentioned are pre- 

 vented by our rendering the urine more copious, and much di- 

 luted. 



"It was proper for me to begin with an account of this fre- 

 quent operation of the substance of cantharides ; but it does not 

 properly touch the medicinal powers of them, which I must 

 therefore now speak of. 



" From the effects mentioned, it is sufficiently evident that 

 the substance of the cantharides goes to the kidneys ; and it is 

 with much probability supposed that such a stimulus applied 

 there must promote the secretion of urine. This effect, how- 

 ever, does not always in fact appear ; and Dr. Smyth Car- 

 michael asserts, that in his frequent exhibitions of the tincture 

 of cantharides, he never once observed the secretion of urine in- 

 creased. In many instances of a strangury produced by the 

 application or exhibition of cantharides, I have not found, 

 though I have often inquired- after it, the quantity of urine 

 sensibly increased : and however it may be explained, though 

 the substance of cantharides operates often upon the neck of the 

 bladder, it may be doubted if at the same time it operates upon 

 the kidneys ; as, along with the strangury so often occurring, 

 I have never met with pains of the back, or other marks of an 

 affection of the kidneys. 



" From these observations, it may be doubted if cantharides 



