f>22 FOODS AND FOOD ADULTERANTS. 



Professor Delafoutaiue over what pure lard should contain. There is some difference 

 in lard on account of (he season at which the hogs are killed, and on account of the 

 age, feed, and other conditions of the animals from which the lard is made. 



MKTHOD OP PKOF. C. B. GIBSON.* 



Five cubic centimeters of the molten sample, at a temperature of 90 to 100 

 C , were dissolved into 45cc of half solution of absolute alcohol and ether; this 

 mixture was allowed to stand eight hours, at a temperature of 5 to 10 C., and 

 the stearine allowed to crystallize out; the supernatant liquid was then poured off 

 and 25cc of the fresh solution added to dissolve any remaining olein and palmitin, 

 and allowed to stand twelve hours at 5 to 10 C. The liquid was then filtered off 

 and the residue collected on a tared filter; this was washed until no more fat glob- 

 ules were deposited on evaporating a drop of (he washings (alcohol and e(her solu- 

 tion); the filter and contents were then dried at a temperature of 30 to 40 C., and 

 by means of desiccator, weighed and the result calculated. All samples were treated 

 at the same time and under (ho same conditions. In the test for cottonseed oil, I 

 submitted 9cc of the molten lanl to the action of sulphuric acid, saturated with 

 nitrous and nitric anhydride, 7cc ; the test kept at a temperature of f> c C., until soli- 

 dification took place, which, in the case of the presence of cotton-seed oil, is produced 

 only after long time; from these results I drew my conclusions. All samples were 

 tested at same time and under same conditions. 



C. B. GIBSON. 



REMARKS BY PROF. C. B. GIBSON.t 



He (ook the two samples that he received from Professor Delafoiitaine, a sample he 

 prepared himself, and a sample he procured in the market, said to be absolutely pure 

 lard, and treated them all by the methods he has described in his written statement ; 

 all the samples were treated iu corked tubes ; the samples all produced different re- 

 sults, some considerably different, and in the two samples he rendered himself there was 

 a slight variation; he tested the process by comparison with the pure lard he had 

 rendered; he did nob make up any samples of mixtures; iu rendering the pure lard 

 for standard samples he cut the fat very fine and put it into a large porcelain dish, 

 and adding water, boiled it from forty-five minutes to an hour; then he squeezed out 

 a portion of the fat, and subjected the residue to a little greater heat and extracted 

 all the fat he could possibly get out by any ordinary squeezing method; the lard then 

 contained some water, which he removed as far as he could by decanting; then 

 heated the lard over a sand-bath, being careful not to heat it so much as to burn it ; 

 but he certainly had it at a sufficiently high temperature to hold the greater part of 

 the stearine in a molten state, and pass it through the filter. 



It would probably depend a little on circumstances which of two samples of lard, one 

 rendered at a low pressure and the other at a high pressure, would contain the most 

 stearine ; speaking casually he should say the one rendered at a high pressure would 

 contain the most ; he means by high or low pressure, a greater or less pressure in 

 squeezing out the lard as is ordinarily done in a small way; ho should think there 

 might be a tolerable variation iu the quantity of lard stearino from this cause, but, 

 f the pure steariuc there ought not to be such a remarkable difference. It depends 

 entirely upon when the lard is produced, when the hog is raised, when killed, what 

 fed upon, and perhaps other conditions, as to how much stearine there may be iu 

 lard; authorities differ on the subject; some claim there is as high as 33 per cent., 

 others less, of lard stoarino ; as far as he has been able to learn, lard stearine varies 

 from 30 to 40 per cent., and pure or chemically pure stearine from less than 1 per 

 cent to about 3 or 3.J per cent, expending upon the conditions ho has referred to : his 

 personal examinations have shown a variation of from a little under 1 per cent, up to 

 about 2J per cent. He should think, the better the hog is, the better would be the 



* Op. cit., p. ir>7. tOn. cit., p. lf>8. 



