Mr. Venables on Siliceous Gravel. 235 



On the contrary, the highest authority on the subject in this 

 country, is decidedly against the opinion that silex does form 

 any part of urinary gravel. Thus Dr. Prout, in his very 

 valuable Treatise on Urinary Disorders, observes, " Silex has 

 been stated to constitute urinary sediments, and even to form 

 a part of urinary calculi in some instances ; but this assertion 

 requires to be better authenticated than it is at present, before 

 it can deserve credit*." Indeed, Dr. Prout communicated to 

 me, personally, his doubts as to the existence of silex, either 

 as gravel or calculus, and expressed his desire of having the 

 point satisfactorily decided. Certainly Berzelius asserts, that 

 it ordinarily exists in the urine, in minute quantity, and that 

 it is probably derived from the water which we drink ; but the 

 foregoing facts tend to prove, that in this country, at least, 

 silex is not apt to appear either as gravel or in the form of 

 urinary calculi. 



I have, however, met with two instances, and which, as 

 affording matter interesting no less in a scientific than in a 

 professional point of view, I deem of sufficient moment to 

 claim attention. From the nature of the facts and the ques- 

 tions which they involve, I have preferred the Quarterly Journal 

 of Science as the most eligible medium of communication. 



The first case occurred in the practice of my friend, Mr. 

 Henry Bird, surgeon of this townf, and was that of a woman 

 thirty-two years of age, married, having two children living, 

 rather unhealthy, the disordered tendencies being to pulmonic 

 irritation. She has been pregnant, in all, seven times, in- 

 cluding two miscarriages ; of the five children born alive, 

 three died and two only now survive. The unfortunate sufferer 

 herself presents every indication of bad health and a broken- 

 down constitution — emaciation, languid, anxious countenance, 

 hectic flush, foul sulcated tongue, hot feverish state of skin, 

 though, at times, subject to perspirations, frequent wiry pulse, 



Allemain, an Italian apothecary, states that he found silica in excessive 



Eroportion — 20 per cent. — in a calculus which he analyzed ; but as he 

 as given no detail of his mode of analysis, some doubts may be enter- 

 tained as to the correctness of the results. — Vid. Ann. de Chimie, xxxii. 

 p. 221, and xlv. p. 222, and Gehlen. Journ., second series, ii. p. 265. 

 * Prout, on Calculus, &c. pp. 28, 29, second edition. 

 t Chelmsford, Essex. 

 OCT.— DEC 1829. R 



