CHAPTEE III. 



ON THE MICROSCOPIC EXAMINATION OF 

 BUTTER. 



Much has been said and written about the use of the 

 microscope in connection with the detection of adulteration 

 in food. By some chemists, pure and simple, this instrument 

 has, until very recently, been viewed with distrust and 

 jealousy ; on the other hand, microscopists are apt to rush 

 into an opposite, and even more dangerous extreme, when 

 their opinions are based solely upon a glance through the 

 magic tubes. 



It has been declared that a microscopic examination with 

 polarised light is a reliable means of distinguishing pure 

 butter from that which contains an admixture of less pala- 

 table fats ; this, we are of opinion, is saying too much for 

 the microscopic diagnosis of butter. 



In butter analysis it is dangerous to rely too implicitly 

 upon microscopic appearances ; the microscope, however, 

 should not be entirely dispensed with, it frequently affording 

 valuable corroborative evidence. 



In no case does any fat in the raw state show crystals ; on 

 the contrary, when a fat is fused the membrane is broken up, 

 and aU the constituents are melted into an oily liquid from 

 which, on cooling slowly, the stearin and pahnitin crystallize 

 out. Beef, mutton, and pork fats show large ceUs of adipose 



