36 FOODS AND FOOD ADULTERANTS. 



salt ami eight or ten drops of water. After Hie water was thoroughly incorporated, 

 the, mass was transferred to a test tube and boiled for 1 minute as in tho case of but- 

 ter. It was theu poured into a "wooden pill-box and allowed to cool as before. The 

 cooled mass presented quite a marked difference in appearance from that obtained from 

 the same substance in Experiment 3. It retained to a great extent the yellow color 

 of tho oleo oil, was of a more granular nature, and in fact resembled boiled butter in 

 every respect. When a small particle was stirred up with olivo oil on a glass slide it 

 separated readily. When covered and viewed with a pocket lens it revealed a mass 

 of globules resembling insect eggs. Under the microscope these globules exhibited 

 essentially tho same characteristics as those obtained from butter in Experiment 1. 

 The crystalline mass of the oleo globule seemed somewhat coarser, and to this condi- 

 tion was ascribed tho fact that the cross, as well as the colors produced by the selcn- 

 ito plate, were less sharply defined than in the globules obtained from butter. The 

 slides prepared from this material were remarkably free from the small detached crys- 

 tals of fat observed in Experiment 3. 



Experiment 8. Having thus discovered that these globular masses may be obtained 

 from pure tallow fat by stiuply observing the conditions which obtain in butter mak- 

 ing, tho following test was made : Nine grams of oleo oil and 1 gram of lard were placed 

 in a small beaker glass and eight or ten drops of a saturated solution of salt in water 

 added. Tho mixture was then gently heated to melt the fats. After shaking violently 

 for a few moments to mix tho salt solution with the fats, the mixture was boiled 

 gently for 1 minute and then allowed to cool as before in a wooden pill-box. Tho 

 microscopic examination of this preparation revealed globular masses which could in 

 no wise bo distinguished from those obtained from pure butter. The crystalline tex- 

 ture was dense, the cross of St. Andrew's plainly marked, and the colors produced by 

 the selenite sharply defined. 



Experiment 9. A mixture of one part of lard to live parts of oleo oil was treated as i n 

 the last experiment with like results. 



Experiment 10. In this test a mixture consisting of '20 per cent, of lard and 80 pol- 

 ecat, of oleo oil was employed. Whether the consistency of this mixture was peculi* 

 arly adapted to tho formation of the globules, or whether possible variations of condi- 

 tions in manipulation were more favorable, the writer is unable to judge from a sin- 

 gle experiment, but tho fact is that in this case the individual '.'butter crystals" 

 were exceedingly large and characteristic. 



The use of polarized light in photo-micrography is also valuable in 

 enabling the photographer to print the light-colored crystals on a dark 

 background. To illustrate some of the forms of crystals of butter and 

 its substitutes as they appear under polarized light a large number of 

 microscopic samples were prepared and photographed by Messrs. Kich- 

 ards and Richardson. Uesults of some of the more interesting of these 

 photographs are herewith transmitted. In all cases the figures are 

 magnified 40 diameters, unless otherwise stated. 



