LARD AND LAED ADULTERATIONS. 537 



described iu a French, work by Theodore Chateau. By that test oils arid fats were 

 treated with different reagents for producing different colors. He has examined all 

 kinds of oils by that method. In some cases good results are obtained, in others they 

 are unsatisfactory. The method is of somewhat doubtful value. Then came the elai- 

 diue test, by which the oleineof a fat is hardened by the action of an oxidizing agent. 

 He does not regard that test as of any value. About 1878, a German rneHiod for an- 

 alyzing oils by means of a standard solution of an alkali was published. He has used 

 that method from then until now, and has found it to produce excellent results. In 

 that method the substance is accurately weighed and treated with hydrate of potash 

 of known value. The result is expressed in milligrams or grams of hydrate of potash 

 required to saponify a stated amount of fat. The standard which is used is 1 gram of 

 fat, equivalent to (blank) milligrams of hydrate of potash. In conjunction with that 

 process, if an oil be examined by the oleate of lead process, which enables one to sepa- 

 rate the equivalent oleate of lead from the equivalent stearic and palmitic acid, you. 

 ascertain the amount of the stearic and palmitic acids derived by difference, or they 



may be estimated directly. 



******* 



His work has been entirely independent of other chemists who have examined those 

 samples of lard. The composition of lard is about 47 of oleic acid and 47 of stearie 

 acid ; be can not give the chemical formula of lard ; the lowest amount of steariue 

 be has found in pure commercial lard was 3S to 40 per cent. ; the highest amount was 

 about 45 per cent. ; by stearine he means the combination of stearine and palmitine; 

 lie has never analyzed lard so as to obtain the tristearine, and has never made the 

 ultimate analysis of either oleine, palmitine or stearine. He does not think there is 

 any difference between the olein of lard and that of tallow;, the chemical character- 

 istics of chemically pure stearine are always identical ; in the mixture of stearine and 

 palmitiue known to the trade as stearine the characteristics would, he supposes, differ, 

 bat he can not describe the differences. Ho believes in the sulphuric-acid test for the 

 detection of cottonseed oil, when used by those who understand it ; he has had a 

 great deal of experience with that test ajid he can detect cottonseed oil by it. He 

 lias made a great many analyses of butter ; and he has used the Augell and Hehuer 

 process, with which he is quite familiar. In the analysis of butter the question of its 

 purity is decided by its percentage of insoluble fatty acids ; his own analyses give 87 

 per cent, as the average of fatty acids in butter; Augell gives 87.34 ; the range is 2. 

 per cent, either way ; if a sample of butter runs over 1 or 2 per cent, above the maxi- 

 mum he has found in pure butter he would condemn it. 



TESTIMONY OF PROF. R. OGDEX DOREMUS. * 



Professor Doremus said he undertook the analysis of the samples 1, 2, and 3, Fowler,, 

 and the samples of pure lard by what is called Muter's process, which consists in pre- 

 cipitating the oleic, palmitic, and stearic acids by a salt of lead; this gives the oleate 

 of lead, the palmitate of lead and the stearate of lead ; the oleate of lead alone is sol- 

 uble in ether. After the oleate of lead was removed by this solvent and after filtra- 

 tinu, it was decomposed by an acid, and a solution of oleic acid and ether was ob- 

 tained. A small part of this solution was drawn off, the ether evaporated, and the 

 residue weighed ; from this the amount of oleic acid was estimated ; the palmitato of 

 lead and the stearate of lead which remained in the filter were removed, decomposed, 

 by an acid, and weighed, giving the palmitic and stearic acids combined. Chemistry 

 has not reached that degree of perfection by which these two last-named acids can 



* Op. cit., pp. -201, -2G-2, 'JG3, -J54, 28o. 



