LARD AND LARD ADULTERATIONS. 527 



method lias been devised for absolutely isolating palinitine, and bo does not know 

 whether or not there is any difference between the crystals of pure stearine and those 

 of pure palmitine ; he can not say whether the crystals procured by him depend on 

 the relative proportions of stearine and palmitiue in the substance from which they 

 are procured ; while he does not claim to speak as authority on chemical subjects, ho 

 thinks the substance from which those crystals were obtained was particularly pure 

 stearine ; he can not positively say whether the crystals obtained from a fat consist- 

 ing of oleiue, steariiie, and palmitine would be those of stearine and palmitine more 

 or less modified as one or the other was iu excess ; he thinks the presence of the oleine 

 would modify the crystals somewhat, but to what extent ho is not able to say. 



MF/riiODS FOLLOWED IX MAKING MICROSCOPIC INVESTIGATION BY MESSUS. TILLEY, 

 BELFIELD, DANFORTH, HAYES, AND ROSE.* 



Dr. Tilley's formula. For the production of the crystals of stearine, whether from 

 beef or hog products, I dissolve the fat in question iu sulphuric ether, 10 grains in 

 2 drachms ; allow the ether to partially and slowly evaporate, and consequently 

 crystals to deposit; decant the ether remaining, wash with ether, decant again and 

 treat with absolute alcohol, then examine the crystals under microscope. Robert 

 Tilley, M. D. 



Dr. ISeifield's formula. Ten grains of the fat are dissolved in Squibb's ether ; the 

 quantity of the latter may be 1 drachm or 2 drachms, or instead of the ether, a 

 mixture of this substance with absolute alcohol in equal parts may be employed as .1 

 solvent. The solution is allowed to stand iu a test tube uncorked for twenty-four 

 hours, at ordinary temperature; at the expiration of this time crystals are observed 

 at the bottom of the tube ; these may be examined directly through the microscope, 

 or supernatant liquid can be poured off and replaced by a drachm of absolute alcohol ; 

 this is subsequently removed and the crystals examined ; the crystals may be mounted 

 for examination in the solvent used or prepared dry. When specimens of pure lard, 

 pure tallow, and mixture of both, within certain proportions, are treated in this way, 

 characteristic crystals are formed by means of which the identity of the specimen 

 can bo established. Essentially the same results are obtained when tho method is 

 varied by changing the quantity of tho solvent, within certain limits, or by repeated 

 washings with alcohol. William T. Belfield. 



Dr. Danforth's formula. The oleiuo is first extracted from tho specimen to be ex- 

 amined by the use of absolute alcohol or a mixture of alcohol and other in equal 

 parts, or by any other method the experimenter may choose to adopt ; the remaining 

 stearine is then dissolved in any one of a number of menstrua, as, for example, ether, 

 turpentine, benzole, oil of Scotch pine, or any other solvent of stearine ; I usually em- 

 ploy turpentine; from this solution crystals arc allowed to form, and tho resulting 

 crystnls are then mounted upon glass slips prepared for the purpose in Canada bal- 

 sam diluted with tweuty-five per cent, chloroform, or a solution of damar, or they 

 may be examined in the original solvent. Auother method I have used recently to a 

 considerable extent, is to place the specimen to be examined immediately in some sol- 

 vent of stearine, as ether, or benzole, or turpentine (usually the latter), in tho propor- 

 tion of ten grains of tho specimen to bo examined to a fluid drachm of the solvent, 

 without first extracting the oleiue; I then watch carefully for the formation of the 

 first crop of crystals ; these crystals are then immediately examined after being 

 mounted in either one of the media that I have already mentioned. Recently I have 

 employed a solution of balsam in chloroform as a mounting medium because it gives 

 the clearest field. The crystals are examined by the use of a one-quarter inch ob- 

 jective and an " A" eye-piece, giving a magnifying power of about two hundred and 

 fifty to two hundred and sixty diameters. Tho difference in appearance between tho 

 lard stearine and beef stearine crystals is clear and definite. Isaac N. Danforth. 



*Op. cit., pp. ll>r,200,201. 



