THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



YoL. IIT. 



New York, Febkuary, 1882. 



ISTo. 2. 



The Detection of Adulteration 

 in Food. 



BY C. M. VORCE, F. R. M, S. 



VI. BUTTER. 



Butter was for a long time regarded 

 as one of the very few articles that 

 could not be successfully adulterated, 

 as it was supposed that any adultera- 

 tion would either be perceptible to 

 taste or smell, or else would cause this 

 very perishable product to spoil. But 

 at the present time butter is as exten- 

 sively adulterated as any other article 

 of food. The first well-known and 

 successful imitation of butter was the 

 now very common oleomargarine, 

 which, however, cannot rightly be 







'^ 



Fig. 3. — Butter. 



called an adulteration of butter, since 

 there is no butter in it. Still it is popu- 

 larly classed, with the later product 

 suene, as an adulterated or artificial 

 butter, and as it competes with pure 

 butter in the markets, and is frequent- 

 ly sold as pure butter, we will, for the 

 purpose of this article, consider it 

 among the adulterations of butter. 



Pure butter, if fresh and sweet, 

 when examined in a thin film under 

 the microscope, is found to consist 

 entirely of very small globules of oil 

 suspended in a limited amount of 

 clear fluid, chiefly water, associated 

 with a small amount of very fine 

 granular matter with which are occa- 



sionally found particles of coloring 

 matter. The square crystals of com- 

 mon salt are always present usually in 

 small, but sometimes in quite large 

 crystals, as shown in fig. 3. The clear 

 fluid of butter is saturated with salt, 

 as may be shown by taking up a little 

 butter on a sharp knife-blade and 

 wiping the edge across the slide, or 

 by using the edge of another slide as 

 in spreading a film of blood. The ex- 

 tremely slight smear thus made on the 

 glass, if examined uncovered, by a 

 I -inch objective, will show a crystal- 

 line structure (fig. 4), at first clear and 



'm 





Fig. 4. — Salt-crystals. 



transparent, but before long gradually 

 becoming dendritic and opaque, at 

 last showing feathery cystallization as 

 the opacity spreads. 



With polariscope and selenite giv- 

 ing a blue field, the polarizing action 

 is faint, but when the field is darkest, 

 a few minute, bright points wil be seen ; 

 the crystals of salt are of the color of 

 the field but with black margins. 



