LARD AND LARD ADULTERATIONS. 531 



CERTIFICATE OF PROF. E. B. STEWART." 



JULY 3, 1883. 



This certifies that I have carefully examined three specimens of lard received from 

 Prof. W. S. Haines on the 20th of June, 1883, and find that they present the charac- 

 teristic of pure hog's lard, free from tallow and cottonseed oil. 



E. B. STEWART. 



METHOD OF EXAMINATION FOLLOWED BY PROFESSOR STEWART.t 



Both pure kettle-rendered and steam- rendered lard were treated with about three 

 times its weight of absolute alcohol at a temperature just sufficient to melt; the solid 

 residuum which separated on cooling was assumed to consist of tristearate of glycyl 

 principally; this was treated with, first, oil of turpentine ; second, petroleum naphtha; 

 third, bisulphide of carbon; fourth, benzole; fifth, Squibb's strongest ether; and, 

 sixth, melted in balsam fir. Pure beef tallow was treated with absolute alcohol in the 

 same way, and subsequently with the same reagents. 



E. B. STEAVART. 



JULY 3, 1883. 



CERTIFICATE OF PROF. S. P. SHARPLESS.t 



JULY 3, 1883. 



I have examined three samples of lard submitted to me by Prof. \V. S. Haines, and 

 marked Nos. 1, 2, 3, Fowler Bros. I have been unable to find any adulteration in 

 these samples, and believe them to be pure hog product. 



S. P. SHARPLESS. 



In explanation of his results Professor Sharpless says : 



He received from Prof essor Haines, two weeks ago, three samples of lard, marked, re- 

 spectively, No. 1, No. 2, and No. 3, since which date he has devoted his time to their 

 examination. The samples were received in tin boxes, wrapped in paper, and properly 

 sealed. The work of examination was commenced ou the 19th of June, and was con- 

 ducted jointly by Professor Doremus, Professor Haines, and himself, at the laboratory 

 of the College of the City of New York. After opening the boxes the contents of each 

 were thoroughly mixed, and then 5 grams were weighed out from each of the boxes; 

 these specimens were submitted to the action of absolute alcohol and the strongest 

 ether, both being carefully tested as to their strength ; he, at the same time, for the 

 purpose of comparison, prepared a sample of tallow, rendering it himself in order to 

 be certain of its purity ; 5 grams of this tallow were also weighed out ; these samples 

 were weighed into small flasks, and the fats of each were melted, and then50cc of the 

 mixture of alcohol and ether was poured over each specimen ; the flasks were shaken 

 until the alcohol and ether had completely dissolved the whole of the fat. This proc- 

 ess is a test that will show whether the lard contained starch or salt or whether there 

 is much water in it ; lard having much water in it will give a clear solution, but will , 

 be milky in appearance ; these lards all gave perfectly clear solutions, with per- 

 haps au occasional particle of wood from the cask ; there was very little fibrous mat- 

 ter in any of the samples ; he has never yet seen samples of lard that were perfectly 

 free from fiber ; these were aa free from it as any he had ever seen ; the flasks were set 

 in a closet, at the same temperature for each, until the next morning, when they were 

 examined. The bulk of the precipitate in the different flasks differed ; in some it was 

 slightly flocculent, in others it adhered to the bottom of the flask ; this latter condition 

 was more marked in the case of this tallow, which formed a thin layer over the bottom 

 of the flask ; the liquid was poured off and 25cc of fresh was added, and the flasks 

 were allowed to stand, with the fresh solvent in them, until the next morning, and 



* Op. cit., p. 228. t Op. cit., p. 233. 



t Op. cit.., p. 228. $ Op. cit., pp. 229-230. 



