REPORT OF THE MICROSCOPIST. 143 



by Professor Weber. The photograph, is a reproduction of one sent 

 by Professor "Weber with the statement that he could not distinguish 

 the crystal thus made from real butter, represented by Fig. 10, as pho- 

 tographed by Prof essor Detmers. Boiled butterine (Figs. 13 and 15), 

 he said, was equally indistinguishable, whereas 13 and 15 are simply 

 poor representations of the oleo crystal. Fig. 14 is a photograph, 

 by the late Doctor Persh, of a crystal of boiled butter. On contrast- 

 ing the butter photographs of Plates I, II, and III with those of the 

 oleo (Plate IV), the difference is seen to be great. But it should be 

 borne in mind that in the practical work of detecting a butter sub- 

 stitute by the microscope the suspected substance must be examined 

 first in the unboiled condition. The oleo crystals alluded to are ab- 

 sent in all commercial butter substitutes. 



NEUTRAL LARD. 



Neutral lard is a product of leaf -lard rendered at the lowest possi- 

 ble temperature. It is said that soda or a small portion of potash 

 added in the rendering facilitates the maceration of the adipose tissue 

 and secures a greater amount of the product. The remnants of tissue 

 are generally observed in the lard thus treated by means of trans- 

 mitted light, and appear as brown bodies frequently enveloped in 

 globules of oil. Neutral lard in bulk is whiter than common lard or 

 "oleo," and contains less stearin than the former, is firmer to the 

 touch, and is deodorized with borax. The crystals, when immature, 

 are small as compared with butter crystals, measuring about one two- 

 thousandths of an inch in diameter, sometimes showing a faint cross, 

 but when large and well formed they do not exhibit a cross. These 

 crystals are composed of acicular spines, proceeding from a common 

 center, as seen in Fig. 5, Plate VI. 



OLEOMARGARINE. 



In some cases freshly made oleomargarine, in consequence of being 

 suddenly chilled in the final stage of manufacture, shows no fatty 

 crystals when examined under the microscope. 



I have lately discovered that a small portion of oleomargarine of 

 this character, mounted on a glass slide 3 by 1 inch, under a cover- 

 glass, heated over a spirit-lamp until the oleomargarine melts, and then 

 cooled slowly, or until the fatty compound appears whitish (a process 

 of about five minutes' duration), is seen on examination under the 

 microscope in the beautifully crystallized forms common to artificial 

 butter. Should the si3ecimen prove to be largely composed of stearin, 

 the crystals will be quite large and well defined, and may be observed 

 in the act of crystallizing. Figure 10, Plate V, represents specimens 

 of this character. Several samples of oleomargarine containing large 

 quantities of stearin reduced with oil to the consistency of butter, col- 

 ored to imitate butter, have been forwarded to this Department dur- 

 ing the present year by the Hon. J. K. Brown, dairy commissioner for 

 the State of New York. 



Thus far I have not found any commercial oleomargarine that has 

 not, on examination by i)lain or polarized light, exhibited at once 

 well-defined crystals of fats. 



EXTRACTION OF COTTON-SEED OIL FROM OLEOMARGARINE. 



I read a jDaper relating to the detection of oleomargarine before 

 the chemical section of the American Association for the Advance- 



