SUPPLEMENT. 401 



oleomargarine. In order to do this, I solicited the friendly aid 

 of a prominent gentleman of this city, who is also well known 

 in business circles in Xew York. I also wrote, independently T 

 to a gentleman in your city, urging him to obtain for me the 

 samples required. 



Desiring also to procure a spacimen of genuine dairy butter, 

 I applied to a well-known citizen of this city, who procures his 

 supplies directly from a farmer. 



After an interval of ten days, I was, in response to my solici- 

 tations, in. possession of three samples of oleomargarine, and 

 one sample of pure dairy butter. The three samples of oleo- 

 margarine are directly from the manufacturers at New York 

 city, and will be referred to as Xos. J, 2, and 3. 



The four samples were subjected to examination under the 

 microscope ; tha objectives used were a l-4th inch of 100 by 

 Tolles, and Spencers late duplex l-4th of 180. 



Samples Nos. 1, 2 and 3, and also the specimen of pure dairy 

 butter, showed many crystals of chloride of sodium ; the crys- 

 tals furnished by the pure butter were, however, cleaner, and 

 more acceptable generally than those exhibited by Nos. 1, 2 

 and 3. 



Samples Nos. 1, 2 and 3, in addition to crystals of chloride of 

 sodium, displayed other crystals, those of nitrate of soda being 

 prominent; while forms closely resembling crystals of choleste- 

 nne were found in considerable numbers. 



Regarding Kos. 1, 2 and 3, it may be remarked that Nos. 1 

 and 2 were, to outward appearance, tolerably fair imitations of 

 genuine butter, and might by the ordinary purchaser be accept- 

 ed and bought as such. N"o. 3 was a poorer counterfeit, and 

 would probably be rejected by most buyers; but if mixed in 

 equal parts with the genuine article, the mixture would be likely 

 to deceive the purchaser. 



In samples Nos. 1 and 2 the microscope displayed the 

 ' feathery crystals" (margarine) described by Prof. Michels, 

 although these were not constantly present in every field exam- 

 ined. By moving the slide, other fields were brought to view in 

 which these crystals were much more prominent than those 

 given in the cut accompanying Prof. Michels' paper. The crys- 



;?(i Microscopy. 



