"So 



SCIENCE. 



[Vol. XII. No. 287 



■'large number of samples of rancid butter seized by the Internal 

 Revenue officers. It seems hardly necessary to say that oleomar- 

 ;garine, owing to its containing a comparatively small amount of the 

 volatile and easily decomposable glycerides, keeps in a ' sweet ' 

 •condition for a much longer time than butter. 



Any instrument that can be placed in the hands of those officers 

 ■who are charged with the enforcement of the law, whereby they 

 •can readily distinguish between the natural and artificial product, 

 ■would be very desirable. 



The difference between fresh, genuine, unmelted butter and oleo- 

 •margarine, which is always made in whole or in part of melted 

 fats, can be readily and clearly detected by a microscope with the 

 aid of polarized light, and with or without the use of a selenite 

 iplate to color the field of vision. It is true that genuine butters are 

 -sometimes accidentally melted, so that while the presence of melted 

 ■fats is not a sure indication that the article is oleomargarine, their 

 •entire absence in the article found in the markets removed from the 

 place of manufacture is a very strong indication that it is butter. 



The use of the microscope for the purpose of observing the pres- 

 ence of melted fats in a fresh sample was first brought to the at- 

 tention of chemists in 1873, in an article on butter, by Dr. I. 

 Campbell Brown, from the ' Liverpool and Manchester Medical 

 and Surgical Reports, 1873,' republished in the Chemical News, 

 vol. 28, p. I, July 4, 1873. Such inspection can be readily per- 

 formed without previous preparation of the sample, and a large 

 iiiumber of samples can be examined in a short time. 



The expense of large instruments with the necessary attachments, 

 ■as usually made for laboratories, rendered them unsuitable for use 

 by local officers in the markets or stores in which butter and oleo- 

 margarine are sold. In December last I came across a convenient 

 and cheap form of microscope, to which under my directions the 

 proper polarizing attachments were added. Owing to delays of the 

 manufacturers a sufficient number of the instruments was not se- 

 cured till last April. These were placed in the hands of the col- 

 ■lectors of internal revenue with full directions for use, etc. 



The instrument consists, first, of a large bell-shaped base, hav- 

 ing at its mouth a silvered mirror acted upon by a spring, and at its 

 •apex a tube fitted with a tightening ring ; second, a draw-tube, 

 working in the tube which forms the upper part of the base, con- 

 taining a good Huyghenian eye-piece, and at its other end a ring 

 to which the analyzer and objective, one-half inch, may be screwed ; 

 and, third, the polarizer, fitted with a small condensing lens, and 

 provided with a milled head whereby it can be rotated, is attached, 

 by suitable means, to the mouth of the base. For convenience in 

 focusing, marks are placed on the draw-tube, giving the approxi- 

 mate focus for ordinary thickness of objects. 



The instrument is carried in a small wooden box eight inches 

 long by five inches wide and deep, containing a number of glass 

 :slides and covers, and having pasted on the inside of the box-cover 

 photo-lithographs of a fresh sample of oleomargarine and of but- 

 terine viewed under polarized light, — ' butterine ' being the trade 

 -name for the product consisting principally of lard with from ten 

 to twenty-five per cent of creamery butter. The box is fitted with 

 a handle. 



A small portion of the fresh sample taken from the inside of the 

 mass — to avoid crystals of salt and accidental melting of the out- 

 side of the sample — with the point of a penknife is placed on the 

 middle of a glass slide and covered. The gentle pressure of the 

 blunt end of a pencil spreads the sample out to make it sufficiently 

 -translucent. On looking through the instrument, at the prepared 

 slide, held towards the direct light from a window, or a gas or 

 lamp fiame placed within a short distance, a sharp focus is quickly 

 obtained, and on rotating the polarizer until the field is dark the 

 presence of melted fats will be readily recognized by the bright 

 ■white particles with which the whole field is illuminated. But 

 where nothing is seen except the characteristic globules, the gran- 

 ular masses of curd, and the cubical crystals of salt, even when the 

 polarizer is turned so that the field passes from the darkest to the 

 lightest, the sample can at once be passed as genuine butter how- 

 ever rancid to the taste or smell it may be. 



Boiled or ' ladle-packed ' butter, made from old rancid butters, 

 melted and churned with a small quantity of milk, and very rancid 

 ■butter may sometimes be mistaken for oleomargarine, but by hav- 



ing a slide of oleomargarine or butterine ready for comparison, the 

 difference is easily perceived. The hard fats, palmitin and stearin, 

 exist in a state of solution in the globules of a fresh sample of but- 

 ter and in the fats of living animals. LIpon being melted and 

 cooled these hard fats separate out in the form of acicular crystals 

 which polarize light, owing to their being double-refracting bodies. 



In the latter part of April I was instructed to proceed to Phila- 

 delphia and New York and assist the local revenue officers in the 

 examination of samples of butter collected in those cities. This 

 investigation was afterwards extended to other cities in May and 

 June, and samples of all grades of butter handled by retail butter 

 dealers were collected and examined, the object being to ascertain 

 to what extent and by whom oleomargarine was sold without com- 

 plying with the law. 



The principal cities and towns in New York and Pennsylvania, 

 and the cities of Baltimore, Washington, Hartford, and New Ha- 

 ven, were visited, and the samples examined by the revenue agents 

 connected with those districts. 



The method of procedure was generally as follows. On a certain 

 day all the division deputy collectors in the city and vicinity in 

 which the examination was to be made were detailed with instruc- 

 tions to visit the stores of all, if possible, retail dealers in butter, 

 except those who had paid the special tax as dealers in oleomarga- 

 rine, and to obtain a sample of each grade of butter dealt in. For 

 this purpose each deputy was furnished with a wooden box, con- 

 taining a gross of half-ounce specimen tubes, with the necessary 

 number of gummed labels and blank forms for noting address, etc., 

 of the dealers visited. At the end of the day the samples collected 

 were brought to the office and placed in an ice-chest. From two 

 to three days were devoted to this canvass. The samples were ex- 

 amined as soon as possible after they were received, and any spec- 

 imen found showing the presence of melted fats was at once thor- 

 oughly investigated and the dealer's store visited and the goods 

 detained, etc. Most of these cases proved on investigation that the 

 so-called butter had been bought from a regular oleomargarine 

 dealer or received direct from the factory. 



The following table shows the number of samples of butters that 

 have been examined in the different cities named and the number 

 found to be oleomargarine. 



Philadelphia, Pen 

 Brooklyn, N.Y. 

 New York, N.Y . 

 Jersey City, N.J. 

 Newark, N.J ... 

 Paterson, N.J ... 

 Hoboken, N.J... 

 Elizabeth, N.J . . . 

 Boston, Mass. ... 

 Lowell, Mass 



No. of 

 Samples. 



656 

 63= 



Sale 



Ma 



Cincinnati, O 



Indianapolis. Ind 



Chicago, 111 



Milwaukee, Wis ... . 



Baltimore. Md 



Washington, D.C 



Four towns, Conn 



Eic:hteen towns, Penn 

 Eleven towns, N.Y... 



Representing 



Stock of 

 Dealers. 



346 

 362 



47S 

 456 

 426 



Oleomargar! 



Edgar Richards. 



Washington, D.C , July 26. 



