Dr. Venables on the Cystic Oxide, &c. ^ 



Great Britain ; and in only one of these have the properties 6f 

 the urine been observed and described. 



Although the instance, the particulars of which 1 am about 

 to detail in this paper, will not perhaps be considered as adding 

 much to the stock of information already extant upon this sin- 

 gular species of urinary concretion, still I am induced to bring 

 it under the review of the scientific ; not only because repeated 

 observations upon so rare a form of urinary derangement must 

 be valuable, but also having had the case under my immediate 

 superintendence for a considerable time, frequent opportunities 

 of attending to the properties of the urine occurred to me ; and 

 which, as tending to confirm in a great degree the very accu- 

 rate description of Dr. Prout, will no doubt prove acceptable. 



„j, , ,, HISTORY OF THE CALCULUS. 



Mechdittt^takd sensible characters. — The calculus was about 

 the size of a very large nut, and passed naturally with the urine 

 through the urethra, by a female, a patient of Mr. Richard 

 Cremer's, a respectable surgeon in this town, who gave it to 

 me with a request that I would examine it, and ascertain its 

 nature and chemical composition. It had a dull whitish ap- 

 pearance, and the outer surface was studded with a few spark- 

 ling shining crystals, which on examination proved to be the 

 triple phosphate. The calculus itself in its external characters 

 and appearance closely resembled the triple one. Its figure 

 or shape approximated very much to that of the kidney. It 

 weighed rather move than twelve grains. On being sawed 

 through, it seemed of a waxy nature, though of much firmer 

 consistence than wax, clogging the teeth of the saw, and giving 

 occasion for frequent cleaning during the operation. Its tex- 

 ture was not laminated ; its fracture was crystalline, and, as 

 has been described, seemed to have a highly refractive density. 

 The specific gravity was 1.714285. 



Chemical characters. — Before the blow-pipe it gave out a 

 peculiar foetid odour, of a somewhat animal nature, but very 

 distinct from that of the lithic acid, leaving a black spongy 

 mass, which when further and more strongly urged, dissipated, 

 leaving a minute portion of whitish ash, not alkaline. Heated 

 with nitric acid upon a slip of laminated platina, it readily dis- 

 solved, and oil being heated over a spirit-lamp till the acid was 



