528 FOODS AND FOOD ADULTERANTS. 



Professor Hayes's formula. Take a suitable vcsaei that caii be well corked and put 

 iu it some of Squibb's otber, add to it lard, or preferably thcstearine from the lard in 

 question, until at a temperature of 85 F. A slight portion of tbo lard or stear- 

 iue remaius undissolved (the stearino may be obtained from lard by makiug a hot sat- 

 urated solution of lard in a mixture of equal parts of absolute alcohol and ether, or 

 some other solvent, and crystallize out the stearino by cooling the solution); the ves- 

 sel is then very tightly corked and the ether heated until the solution is perfectly 

 clear ; then the vessel is placed in water, or left in a room, at a temperature of from 

 60 to 70 F. ; the slower the solution cools the larger will be the crystals; the 

 ether is then decanted from the crystals and the crystals washed with cold ether 

 or a mixture of absolute alcohol and ether ; the crystals are again washed with ab- 

 solute alcohol, after which afresh portion of absolute alcohol is put on the crystals 

 and allowed to stand. The crystals may bo mounted either iu Canada balsam, glyc- 

 erine jelly, or dry. In examining the crystals I usually employ a fifth objective and 

 a " B" eye-piece. The difference in form of the beef and lard stoariue crystals fur- 

 ui>hes a ready means for their detection. Plymmon S. Hayes. 



Dr, Rose's formula. Take 1 gram of the fat and dissolve iu absolute alcohol, al- 

 low it to stand until crystals form, decant off the solution, and wash with repeated 

 portions of absolute alcohol, finally remove the alcohol by heat, and dissolve in tur- 

 pe. .tine and set aside to crystallize ; when crystals form remove with a pipette and 

 examine them with the aid of a microscope ; the crystals formed from beef products 

 are quite different from those obtained from hog products. P. B. Rose. 



AX OUTLINE OF DR. ROSE'S METHOD OF CHEMICAL ANALYSIS.'' 



Take a definite quantity of the article to be examined, add nine times its weight of 

 a mixture of equal parts of ether and absolute alcohol (the absolute alcohol used was 

 but 93 per cent, alcohol), thoroughly agitate, place the jar in water, kept at 65 F. for 

 twent3~-four hours ; the clear portion is then decanted off and about one-half as much 

 more of the alcohol and ether is again added; agitato and allow the jar to stand 

 for twenty-four hours in water at the constant temperature of 05 F. ; the liquid 

 portion should then be decanted off and finally filtered ; the filter containing the res- 

 idue placed in a jacketed filter filled with water and kept at the temperature of (>.">' 

 F. ; the residue on tbe filter is washed with a mixture of alcohol and ether, cooled 

 to the temperature of 65 F. ; the filter and residue are dried and weighed, the 

 filter being counterpoised by a second filter. 



The following are the amounts taken and the results : 



Grams. 



Prime steam lard taken 10. 905 



Residue obtained 2.846 



Kettle- rendered leaf lard taken 10.351 



Residue obtained 3.250 



No. 1 sample taken 10. 065 



Residue obtained 2. 5CO 



No. 2 sample taken 9. 979 



Residue obtained 2. r>-,'4 



No. 3 sample taken 9.599 



Residue obtained 2.409 



The other experiments were conducted in like manner except that the temperatmo 

 was kept at 50 and 60 F., respectively. 



P. H. KOSK. 



Op. cit., p. 202. 



