30 



On the " Cystic Oxide^^ Calculus ; and on the sensible, mecha- 

 nical, and chemical Properties of the Urine in this Dia~ 

 thesis. — By Robert Venables, M.B., St. Mary Hall, 

 Oxford ; Physician to the Chelmsford Provident Society, 

 &c. &c. 



The occurrence of calculi of this description is so extremely 

 rare, that an opportunity of meeting with one may be con- 

 sidered as an era in practical medicine. Whether their occur- 

 rence be really so rare, or that many opportunities pass un- 

 heeded in consequence of the inattention so generally prevalent 

 with respect to the more obscure forms of urinary disease, it is 

 not my object on the present occasion to inquire. The cystifc 

 oxide was discovered by Dr. Wollaston for the first time in 

 1805 ; and in 18 LO, when he first published an account of its 

 properties in the Philosophical Transactions, he had met with 

 only two instances. Soon after Dr. Wollaston's description. 

 Dr. Henry, of Manchester, discovered two specimens in his 

 private collection*; but nothing seems to be known with 

 respect to the histories of these cases. 



Dr. Marcet met with three instances of this singular sub- 

 stance, and he has published a summary history of each, so 

 far as he had an opportunity of becoming acquainted with it. 

 For the details, imperfect as they are, I must refer to his work 

 on " Calculous Disorders |." Mr. Brande met with two in- 

 stances, the histories of which are also confined and unsatis- 

 factory. The reader desirous of further information is referred 

 to Mr. Brande's account J. 



Dr. Prout, at the time of publishing the second edition of 

 his very valuable work on the urinary organs, had met with 

 only one instance. The detail appears to me the most valu- 

 able history extant, because it describes the general and very 

 singular properties of the urine : objects of primary importance 

 in calculous and all other urinary affections. Hence then it 

 appears, that during a period of nearly twenty-five years — 

 from 1805 to 1830 — only ten instances of the cystic oxide 

 have been noted in the whole of the medical experience of 



• Henry, Med. Chirurg. Trans, vol. x. p. 140. f Pages 90—96. 

 X Royal lusU Journal; vol. viii. p. 71. 



