H9 



the usual methods hitherto described, the author proposes the follow- 

 ing process. The solution containing the iron is to be peroxidized 

 by nitric acid, then neutralized while boiling by carbonate of ammo- 

 nium ; the iron falls, while the other metals, which Mr. Herschel sup- 

 poses to be manganese, cerium, nickel, and cobalt, remain in solution. 

 A few precautions are necessary to insure success in this operation ; 

 such as, that the solution must contain no oxide of manganese or ce- 

 rium, except in their states of protoxide ; and that during the pre- 

 cipitation the solution should be duly diluted and agitated ; and the 

 latter portions of the alkaline solution, carefully added so as to avoid 

 its excess, though slightly surpassing the point of saturation, give 

 rise to no error or inconvenience. 



Mr. Herschel concludes this paper with some observations re- 

 specting those peculiarities of the peroxide upon which its separation 

 in the above cases depends, and gives some instances of its application 

 to practical analysis. 



On the Re-establishment of a Canal in the Place of a Portion of the 

 Urethra which had been destroyed. By Henry Earle, Esq. Sur- 

 geon to the Foundling, and Assistant Surgeon to St. Bartholomew's 

 Hospital. Communicated by Sir Humphry Davy, Bart. P.R.S. 

 Read April 12, 1821. [Phil. Trans. 1821, p. 300.] 



In this paper Mr. Earle details the case of a man whose urethra 

 was much injured in the perineum by a fall in the year 1813, and 

 who continued to suffer difficulty of making water till 1819, when 

 he was attacked with retention of urine, followed by effusion and 

 mortification ; by which the integuments of the perineum, and more 

 than an inch of the canal of the urethra, sloughed away ; forming 

 afterwards a large smooth cicatrix, above and below which the mu- 

 cous membrane was still visible. After properly dilating the anterior 

 part of the -urethra, Mr. Earle performed the following operation : 

 A portion of integument was removed, about 1^ inch long and i inch 

 wide, on the left side of the cicatrix ; an incision was then made 

 across the perineum, so as to pare away the callous edges of the ure- 

 thra, and the cutis dissected from a portion of the integument on the 

 right side of the perineum, leaving a smooth space between the cut 

 surfaces to form the lining of the new canal. The integuments on 

 the right side were then dissected up, turned over a catheter, and 

 brought in contact with the opposite groove, being kept in their 

 place by two ligatures, some straps of adhesive plaster, and a band- 

 age. This first operation was attended with partial success ; and the 

 patient's general health being disordered, nothing further was done 

 till the summer of 1820, when a second operation was performed as 

 follows : A deep groove was made on the right side of the surface 

 denuded of its cutis ; a portion of integument was then detached from 

 the left side, and properly retained by the quill suture and adhesive 

 plaster. About two thirds of the canal were thus completed ; and 

 by a third operation, upon a smaller scale, the cure was ultimately 



