November 19, 1886.] 



SCIENCE. 



457 



those interested in this subject of this very fact thus 

 acknowledged by Science. But be it remembered, 

 that, in the re-crystallization that takes place after 

 manufacture, it is not the ' oleo ' crystal with cross 

 that re-appears, but a stellated body resembling; lard. 

 Normal butter always shows a uniform tint ; lard 

 and tallow, as sold everywhere, show prismatic 

 colors. What Professor Weber alludes to is strictly 

 neither lard nor tallow, but a specially prepared 

 material known as ' oleo ' and ' neutral lard.' These 

 he chills suddenly to prevent crystallization, a con- 

 dition not suggested by the broad statement contained 

 in my paper. No unbiassed mind would compare the 

 evanescent results of this experiment with an ounce 

 of ' neutral lard ' ©r ' oleo,' with the constant crys- 

 talline condition of the million of pounds sold daily 

 in our markets. 



With res;ard to the optical test of oleomargarine 

 observed in the use of polarized light and selenite 

 plate, I have said : " If the sample is submitted to 

 the action of polarized light and selenite plate, and 

 appears of a uniform color according to the color of 

 the selenite used, we have another indication that 

 the substance is pure normal butter, which, under 

 these conditions, never exhibits prismatic colors. 

 Sometimes large crystals of salt cause the appear- 

 ance of prismatic colors in pure butter, by refraction : 

 these should be removed. Butter that has been ex- 

 posed to light until it is bleanlied, or butter that has 

 been in immediate contact,, for a long time, with a 

 substance that absorbs its oil, as when placed in 

 wooden tubs, has undergone a chemical change, and 

 should not be considered as normal butter " (extract 

 from the Sturtevant open letter, which Professor 

 Weber professes to have reviewed). But even butter 

 of this description never exhibits crystals resem- 

 bling those of either lard or 'oleo.' The prismatic 

 colors of an abnormal butter, described by Professor 

 Weber, and accounted for by me in my earlier 

 papers as observed in decomposing or over-heated 

 butters, etc., could not be mistaken by any but a 

 novice for the gorgeous tints seen, with and without 

 the aid of selenite plate, in butter substitutes in 

 general. In a letter addressed to me, April 8, cur- 

 rent year, Professor Sturtevant says: "Your claim 

 for the selenite plate received our attention a long 

 time ago, as we observed it in Professor Wiley's re- 

 port for 1884. This test seems to offer promise of 

 value." Professor Wiley, chemist of the depart- 

 ment of agriculture, says : " Pure unmelted butter, 

 ■when viewed through a selenite plate by polarized 

 light, presents a uniform tint over the whole field of 

 vision. On the other hand, butter substitutes give 

 a field of vision mottled in appearance. This phe- 

 nomenon is so marked, that, with a little experience, 

 the observer will be able to tell a genuine from an 

 artificial butter with a fair degree of accuracy. 

 While the examination should never stop with this 

 ■optical test above, it can be advantageously used as 

 a preliminary step." My bulletin was issued in 1881; 

 the agricultural report for 1884 was issued in 1885. 



In a footnote to my paper already mentioned 

 (Hitchcock and Wall's Journal), the following ap- 

 pears : " Well-made oleomargarine may be quite free 

 from any crystalline appearance, at least while fresh. 

 . . . The sudden cooling on ice seems to prevent the 

 immediate formation of crystals, but it is not un- 

 likely that these will gradually form in course of 

 time." Thus it is shown that Professor Weber was 

 anticipated by seven years in this case. A tub of 



fresh oleomargarine, direct from Armour's factory, 

 Chicago, the present month, was examined as soon 

 as received. Stellated crystals were at once ob- 

 served in it, and the entire field was covered with 

 prismatic colors. 



Professor Weber states that a sample of butter 

 subjected to heat and cold in his laboratory, but 

 which did not actually melt, showed under the naicro- 

 scope prismatic colors, and he pointedly, although 

 mistakenly, asserts that this butter fairly represents 

 the condition of butter generally. In a paper read 

 before the American society of microscopists, August, 

 1885, published in the Proceedmgs of the society, I 

 say : " When oleomargarine or butterine is newly 

 made, crystals of fat are seldom observed in it when 

 viewed under the microscope ; but iti course of time, 

 owing to its being subjected to light and increase of 

 temperature in stores, it exhibits crystals of fat more 

 or less. In butter substitutes of commerce the crys- 

 tals are seldom absent." 



Science f ui'ther saj'^s : ' ' Apparently, Dr. Taylor 

 prepared his annual report with these results in 

 mind, for there, and in his paper before the annual 

 meeting of the American society of microscopists at 

 Chautauqua, Aug. 10-16, he gives his method a still 

 different exposition." Answer : The most important 

 loart of this sentence, to me, is its personal character. 

 It contains an indirect charge that I so altered my 

 official report to the commissioner of agriculture as 

 that it might appear that I had anticipated Professor 

 Weber in his novel views and experiments. It is 

 sufficient to say that my official repoi't was placed in 

 the hands of Colonel Nesbit, chief clerk of the de- 

 partment of agricultiire, at least six months before 

 Professor Weber made his experiments. The points 

 to which Science alludes are all contained in my re- 

 port to Professor Kellicott, secretary to the American 

 society of microscopists, at Buffalo, N.Y., sent him 

 by mail Oct. 7, 1885, and were not afterwards altered 

 by me, as the publishing committee will testify. In- 

 dependently of all this, there is on file in the depart- 

 ment of agriculture a copy of my original rejiort, 

 made by one of the clerks of the statistical bureau, 

 over one year ago, which agrees with my jDublished 

 official report. Science further says : ' ' Dr. Taylor's 

 first step is now to search for fat crystals in the test 

 sample by plain transmitted light." Answer : As 

 has been shown, this was my method for the first 

 several years, for the simple reason that lard crystals 

 are by this means easily detected, but I subsequently 

 discovered that the crystals of beef -fat could not be 

 proiaerly defined without the aid of polarized light. 

 Science further says : ' ' By the application of polar- 

 ized light, ' amorphous crystals,' whatever these may 

 be, may be detected." Answer : I have applied this 

 term, ' amorphous crystals,' to mottled fats which, 

 seen by polarized light without selenite, exhibit no 

 particular form or structure, but. seen by polarized 

 light with selenite plate, exhibit specks and prismatic 

 colors, thereby showing their crystalline condition. 

 Science further says : "To determine whether these 

 amorphous crystals are of beef-fat or of lard, the 

 sample is boiled and slowly cooled, as already de- 

 scribed, and mounted in oil." Answer : In my offi- 

 cial report I say : "Having first examined the sus- 

 pected material under the microscope, it may be 

 boiled." The precaiation of a preliminary examina- 

 tion by polarized light is highly necessary, for, should 

 the sample contain a large per cent of butter, boiling 

 might cause it to crystallize in large globose bodies, 



