VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. (5l 



bladder, they have a quite contrary effect on gall-stones. So far from dissolving 

 these last, our author has frequently found that these waters envelope them with 

 their tophaceous crust. Dr. Whytt has observed, that lime-water has no solvent 

 power on gall-stones. Hence we draw another proof of the analogy of lime- 

 w^ater with Carlsbad water. 



If it should be wondered at, how it comes to pass that the urine of those who 

 drink these waters should have the power of dissolving the stone, it is necessary 

 to inform our readers, that this urine contains nearly the same properties which 

 the water originally had. It has before been observed, that these waters are 

 impregnated with an alkaline principle, and consequently ferment with acids. 

 The urine of those who drink them, if made before dinner, has the very same 

 quality as our author has frequently experienced ; especially if the accustomed 

 quantity of water is taken, and nothing else is drank upon them. The custom- 

 ary dose at Carlsbad is not less than 6, 7 or 8 pints of water taken every morn- 

 ing : for which reason we are not to wonder that the urine has the property of 

 dissolving the stone in the kidneys and bladder, if it be long retained. And our 

 author makes no doubt but that the injection of these waters into the bladder, 

 would be very powerful in relieving calculous complaints ; though this he had 

 never tried ; neither was he much induced to it, as the urine is possessed of all 

 the powers which he was in search of. 



It remains that we just take notice, by what means these waters are possessed 

 of their solvent power. It is well known that acids, more especially mineral 

 ones, dissolve animal calculi, by acting on their terrestrial parts, dividing their 

 masses, and thus becoming neutral. These effects do not arise from alcalies, as 

 they leave terrestrial substances untouched. If sometimes we carefully attend to 

 the operations of nature, we now and then make discoveries which must other- 

 wise have escaped us. If we pour nitrous or vitriolic acid on that stony sub- 

 stance called crabs-eyes, and let them remain in the glass for a considerable time 

 perfectly still, we shall find at the bottom of the vessel, after the terrestrial parts . 

 are tVioroughly dissolved, a membranous substance or jelly, exactly in size and 

 figure resembling the crabs-eyes, and which the acid had left untouched. Exactly 

 such a gelatinous mass our author has observed in stones of the bladder, more 

 particularly in small ones, after dissolving them in acids. When crabs-eyes are 

 infused in an alkaline lixivium for a considerable time, we see no change in them, 

 which can be properly called a solution : about them we observe a certain viscid 

 appearance like a cloud; when that is taken away, and the crabs-eyes are dried, 

 and afterwards weighed, they have not only lost part of their weight, but are 

 become much more friable ; which is a great argument that they have lost some- 

 thing. When afterwards these crabs-eyes are washed with warm water, to carry 

 off the alkaline matter adhering to them, and afterwards set to dissolve in acids, 



