220 PHILOSOPHICAL TRANSACTIONS. [ANNO 1797. 



Though I do not at present presume to draw conclusions with regard to the 

 treatment of all the diseases in question, some inferences cannot pass unobserved. 

 The sand from the pineal gland, from its frequency hardly to be called a disease, or 

 when amounting to disease most certainly not known by its symptoms, would, at 

 the same time, if known, be wholly out of the reach of any remedy. The calculi 

 of the prostate are too rare perhaps to have been ever yet suspected in the living 

 body, and are but indirectly worthy of notice. For if by chance one of them 

 should be voided with the urine, a knowledge of its source would guard us against 

 anerror we might otherwise fall into, of proposing the usual solvents for urinary calculi. 



The bone-earth calculus, though so nearly allied to the last, is still manifestly 

 different, and cannot be supposed to originate from that source; but if ever the 

 drinking of water impregnated with calcareous earth gave rise to a stone in the 

 bladder, this would most probably be the kind generated, and the remedy must evi- 

 dently be of an acid nature. With respect to the mulberry calculus, I fear that an 

 intimate knowledge of its properties will leave but small prospect of relief from any 

 solvent; but by tracing the source of the disease we may entertain some hopes of 

 preventing it. As the saccharine acid is known to be a natural product of a species 

 of oxalis, it seems more probable that it is contained in some other vegetables or 

 their fruits taken as aliment, than produced by the digestive powers, or secreted by 

 any diseased action of the kidneys. The nutriment would therefore become a sub- 

 ject of minute inquiry, rather than any supposed defect of assimilation or secretion. 



When a calculus is discovered, by the evacuations, to be of the fusible kind, we 

 seem to be allowed a more favourable prospect in our attempts to relieve: for here 

 any acid that is carried to the bladder will act on the triple crystals, and most 

 acids will also dissolve the phosphorated lime; while alkalies, on the contrary, 

 would rather have a tendency to add to the disease. Though, from want 

 of sufficient attention to the varieties of sediment from urine, and want of 

 information with regard to the diversity of urinary calculi, the deposits peculiar 

 to each concretion are yet unknown ; it seems probable that no long course of 

 observation would be necessary to ascertain with what species any individual may 

 be afflicted. 



The lithic, which is by far the most prevalent, fortunately affords us great va- 

 riety of proofs of its presence. Particles of red sand, as they are called, are its 

 crystals. Fragments also of larger masses, and small stones, are frequently passed; 

 and it is probable that the majority of appearances in the urine called purulent, 

 are either the acid itself precipitated too quickly to crystallize, or a neutral com- 

 pound of that acid with one of the fixed alkalies. Beside this species, the fusible 

 calculus has afforded decisive marks of its presence in the case which furnished me 

 with my specimen of triple crystals; and by the description given by Mr. Forbes 

 (in his Treatise on Gravel and Gout, ed. 1793, p. 6*5), of a white crystallized 

 precipitate, I entertain no doubt that his patient laboured under that variety of the 

 disease. 



