70 ANALYSIS AND ADULTERATIONS OF BUTTER. 



Its use may be indicated, when one or two per cent, of acid 

 need not "be considered, but it is quite inadmissible for 

 accurate determinations. 



There is no longer any doubt, therefore, that a notable pro- 

 portion of soluble acids is present in the fat of butter. Yet 

 practically the results, obtained in the multiplicity of ways 

 described, appear to us to possess but little value, and we 

 cannot concede to the determination of the soluble acids so 

 great an importance as was attributed to them by Dr. Muter, 

 who suggested that they should always be determined besides 

 the quantity of insoluble acids, in order to have a check or 

 corroboration upon the estimation of the insoluble acids. 

 The following are some of the reasons which induce us to 

 place little value upon the soluble acids. We do not, however, 

 wish it to be understood that we altogether deny the useful- 

 ness of their determination, which in some few cases, where 

 as much evidence is desirable as it is possible to bring forth, 

 may really be indicated. 



A numerical determination cannot be used to corroborate 

 another one, and if necessary to correct the results obtained in 

 another way, unless it is at least as accurate as that which it is 

 meant to corroborate. Eut since exact and decisive quantitative 

 results have not been hitherto obtained by the employment of 

 either of the methods just sketched out, for the estimation of 

 the soluble acids, and as moreover any figures, inaccurate as 

 they are, can only be arrived at by the expenditure of much 

 trouble and time, and as, on the other hand, the determina- 

 tion of the insoluble acids presents no difficulty whatever, 

 whether the filter or the flask washing be employed, we 

 cannot but come to the conclusion, that the determination of 

 the soluble fatty acids either as corroboration of the insoluble 

 acids, or used alone, is far inferior in accuracy to that of the 

 insoluble fatty acids. Practically their determination is useless, 

 and when analyses are to be executed with dispatch, in large 



