258 Proceedings of Boyal Society of Edinburgh. [sess. 
evidence in favour of the silver process, for a constant difference such 
as he obtains would not be possible were the compound (we will call 
it urate of silver) of unfixed and varying composition, and therefore 
his own results prove the proposition he intended to destroy. 
The constant difference of 14 mgrms. is due, at any rate in part, 
to the imperfections of his own method, which he had never taken 
the trouble, to test, merely comparing his results with those 
obtained by the unexact method of Heintz. This difference has 
been reduced to within the limits of manipulative error by Hermann 
and Czapek, when comparing the silver method with the method 
introduced by Ludwig. 
Mr Gossage has also criticised my method on the same grounds 
as Salkowski, but I am afraid that his results must suffer a totally 
different explanation. He gives five estimations, in which he 
obtains the uric acid by the silver method and by Salkowski’s 
method. His results may therefore strictly be compared with the 
exactly similar ones of Salkowski and Jolin. His average difference 
is 32 mgrms., which is more than the extreme difference obtained 
by the other chemists (28 mgrms.). If we accept the results of 
Salkowski and Jolin as trustworthy we are forced to look upon 
Mr Gossage’s analyses as untrustworthy, and indeed his least mani- 
pulative error is greater than the greatest ever quoted by them. 
(Lor a full discussion of this question see a paper appearing in the 
next number of the Zeitschrift f. physiol. Chemie). 
