532 FOODS AND FOOD ADULTERANTS. 



then their contents were filtered, the precipitate washed \vith a little absolute alcohol, 

 and weighed. Sample No. 1 gave 4.35 per cent, of precipitate ; No. 2 gave 2.99; No. 

 3 gave 2.4, and the tallow gave 5.3 per cent, of precipitate. At the same time an- 

 other series of experiments was tried by weighing out the same amount, of lard and 

 adding to it the mixture of alcohol and ether; in this case the lard was not melted 

 previous to the addition of the alcohol and ether ; after these were added theflaskswere 

 shaken thoroughly and stood in a water-bath at the temperature of Crotou water, 

 which at that time was about 72 F., the water being allowed to run around the 

 flasks; they were left standing in the water in this way for a little over two hours, 

 during which time they were shaken every fifteen minutes; at the end of this time 

 the contents were allowed to settle ; the liquid was then poured off and 25cc more of 

 the solvent was added, again shaken, and the residue of each sample was collected 

 on filters, which had previously been weighed ; this series of tests produced a little 

 higher per cent, of residue in every case than the former. No. 1 gave 5.63 ; No. 2 

 gave 4.17 ; No. 3 gave 3.G9, and it was found impossible to filter the pure tallow on 

 account of the large mass of crystals it gave. The day after this test they received 

 a sample of pure prime steam lard from Chicago, rendered under the supervision of 

 Dr. Tilley ; he made two parallel experiments upon this pure lard ; the first one gave 

 a residuum of .44 of 1 per cent. ; the second gave 3.14 per cent. These samples were 

 taken from the same mass of lard at the same time, and were treated with exactly 

 the same solvent of alcohol and ether ; during the process they stood side by sido in 

 the same closet, were filtered off at the same time, weighed at the same time, and in 

 every way treated alike, and yet one gave nearly eight times as much residue as tho 

 other. In connection with Professors Remseu and Witthaus he tried another series 

 of experiments, following out the same method as in the first series, with results sub- 

 stantially the same as in the first experiment, which he has detailed so far as the lard 

 was concerned. In this experiment there was also a mixture of lard and tallow, but 

 ho did not find that the addition of the tallow made any perceptible difference in tho 

 result. This experiment will probably be more fully described by Professor Remsen. 



CKUTIFICATE OF PROF. IRA RKMSEN.* 



CHICAGO, July 5, 1883. 



I hereby certify that I have examined by chemical methods tho three samples of 

 lard designated as Nos. 1, 2, and 3, "Fowler," submitted to me by Prof. W. S. Haines. 

 and have failed to find any foreign substance in them. I am, therefore, of the opinion 

 that the samples are pure lard. 



IRA REMSKN. 



Professor Remseu t stated that he received from Prof. W. S. Haines, for ana^sis, 

 three samples of lard, designated 1, 2, and 3, " Fowler," aud has been working on 

 them constantly for about ten days, to a considerable extent night and day. When 

 these samples were first submitted to him he set about a very careful search through 

 the literature on the subject to determine what method ought to be adopted in the 

 examinations of them. He was disappointed by finding that the chemical study of 

 lard had, apparently, received very little attention. Tho methods for tho chemical 

 examination of Jard which have been, perhaps, the most frequently employed, a;o 

 similar to those which are used in the examination of butter; indeed, tho chemical 

 knowledge of butter is much more general than that of lard. After considering the 

 subject he decided, as ho thinks most do who are called upon to investigate lard, to 

 adopt as an experimental method that of Hussoii, which is based on a very sim- 

 ple principle. Fats are known to differ in the proportions of oloino, pnlmitino, and 

 etearino contained in them. In liquid fats there is a larger proport ion of oleine, and ft 

 less proportion of stearino than in those of a more solid character. In case a fat 



Op.cit., p. 246. tOp. cit.,pp.238, 239,240,241,245,246. 



