VOL. XIV.] PHILOSOPHICAL TRANSACTIONS. IQ 



as I concluded by comparing chemical products, which I only very briefly relate. 

 Having cleared the bone of marrow and fat by boiling it in water, I distilled it, 

 and obtained about 3 drams and a half, from an ounce of bone, of a volatile 

 liquor impregnated with salt, that smelt very different from spirit of urine, and 

 nearer that of hartshorn : I found the caput mortuum, as to weight, very con- 

 sonant ; and also could extract no manner of salt from it. For which reason 

 refiners make their cupels of calcined bones, as they are forced to dulcify (which 

 they call washing out the salts of) other ashes, before they can make cupels of 

 them. In this also it agrees with the calculus humanus, vulgarly so termed, 

 that few acids will dissolve it, excepting those that are nitrous, nor do these 

 work on it very vigorously. They must however be allowed to differ in their 

 specific gravity, the calculus not having so close and compact a texture as the 

 bones have. For bones I have found twice as heavy as their bulk of water.* 



^n Index of some Experiments made in this short Treatise. — Several stones of 

 the bladder and kidneys were distilled ; and all afforded volatile urinous salts, 

 which ferment on any acids. Bones were distilled, and found to be of similar 

 principles. — Petrified water affords only fresh and clear water on distillation. — 

 Calculi examined hydrostatically, were found in proportion to their bulk of 

 water, as 5 to 4. — ^We weighed flint, crystal, petrified water, Welsh diamonds, 

 petrified wood in water ; and found them all very near of a specific gravity, and 

 almost as heavy again as our calculous matter. — We weighed bones hydrostati- 

 cally ; and found them twice as heavy as their bulk of water. — Bones not easily 

 wrought on by common acids, only by nitrous ones, and that without ebullition. 

 — Various unsuccessful attempts made to dissolve the callus, by acid and acri- 

 monious menstruums, some were vegetable and some mineral, as spirit of salt, 

 of vinegar, of venus, oil of vitriol, &c. also with alkalisate acria, as sal fraxini, 

 which corrodes glass, lapis infernalis ; but none would touch it except nitrous 

 acid. — The coagulation of spirit of wine has no place here. 



Experiments to be made, relating to the Therapeutic Part. — ^To discover in- 

 nocent menstruums that may dissolve the stone. — To examine the condition of 

 the urine sometime before a paroxysm, both as to its specific gravity and con- 

 tents. — And also during the paroxysm, to regard the painful water sometimes 



• But Dr. Slare found (as he mentions in a former part of this paper) human calculi to be " only 

 as heavy as their bulk of water and a fourth part more." It was not till within these few years that 

 the constituent parts of the urinary calculus were fiiUy determined. It has been ascertained by 

 modern chemical analyses that phosphate of lime (earth of bones) is a frequent ingredient in human 

 calculi. Thus far has Dr. Slare's conjecture been verified. It is however but one of the ingredients, 

 and that not always, of these morbid concretions. Oxalate of lime is another ingredient, and the 

 most frequent of all, uric acid and urate of ammonia. 



D 2 



