3G REPORT OF THE COMMISSIONER OF AGRICULTURE. 



conditions still imposed upon me has been made to secure from those 

 who receive the seeds more accurate and reliable reports as to their 

 practical value to American farmers. 



MICROSCOPICAL DIVISION. 



The recent enactment of a United States law regulating the man- 

 ufacture and sale of oleomargarine has operated to increase the work 

 of this division. Many letters have been received and answered by 

 the microscopist from scientific men, professors in colleges, universi- 

 ties, and experiment stations, as well as from editors of scientific and 

 literary publications, and especially from those engaged in the dairy 

 interests of the country, asking for such information as may be of 

 value in relation to the best methods of detecting butter substitutes. 



During the current year the division has made over one thousand 

 examinations of pure butter, of butter substitutes, and of the fats of 

 various animals. The Microscopist believes that every statement 

 heretofore emanating from this division is amply confirmed by the 

 results of his investigations during the present year relating to the 

 crystallography of the fats of animals and plants, and particularly with 

 regard to the views advanced in his former report, that the fats of 

 various animals yield typical crystals, which may at once be distin- 

 guished from one another. In the production of these typical crys- 

 tals the respective fats are subjected to a simple uniform treatment. 

 While nearly all the fats are composed of palmatine, stearine, and 

 oleine, they contain these glycerides in greatly varying proportions, 

 and there may be other considerations, as yet unknown, which con- 

 tribute to the remarkable diversity seen in the composite fats of dif- 

 ferent animals. Many specimens have been mounted and sent to the 

 various agricultural colleges and experiment stations. A large num- 

 ber of photographs representing the diverse character of the typical 

 fatty crystals have also been made and distributed to scientific men, 

 the object being to demonstrate that the fat of one animal may be 

 easily distinguished, within certain limits, from that of another. 

 Over one thousand specimens of fats, including the butter of noted 

 breeds and various compositions of oleomargarine, have been made 

 during the current year and results noted. 



Preliminary experiments have also been made in testing butter with 

 relation to the effects of silo feed, grass feed, dry feed, &c. It is the 

 opinion of the Microscopist that there are strong indications- that 

 within certain limits the butter crystals are affected as to their form 

 and density by the breed and character of food. 



Butter is being prepared at present by prominent dairymen and 

 farmers of several States who have especially fine breeds of cattle 

 with a view to having microscopic observations made in regard to 

 this question. Photographs, exhibiting modifications of the butter 



