COMMERCIAL FEEDING STUFFS OF THE UNITED STATES: 

 THEIR CHEMICAL AND MICROSCOPICAL EXAMINATION. 



INTRODUCTION. 



K.\ tensive investigations on commercial feeding; stuffs have been 

 conducted by a number of experiment stations, in connection with 

 tin* enforcement of the feeding-stuff laws in the various States. 

 Those laws, however, usually require a guaranty as to fat and protein 

 only, and consequently the examinations by the stations have been 

 in most cases limited to these two constituents. In a few cases 

 determinations have also been made by the stations of ash, crude 

 liber, and nitrogen-free extract by difference, but practically i <> 

 jit tempt has been made to determine any of the various carbohydrates 

 that constitute the so-called nitrogen-free extract. 



From a scientific as well as practical point of view a more complete 

 analysis seemed desirable, as such data would give a better idea of 

 the true composition of a stock food, and thus make possible a fairer 

 comparison of the relative feeding values of the different varieties. 



In addition to the chemical analyses, a microscopical examination 

 of the stock foods was made by B. J. Howard, chief of the microchem- 

 ical laboratory, and his report is appended. 



CHEMICAL EXAMINATION. 

 COLLECTION OF SAMPLES. 



During the spring of 1904, arrangements were made with the 

 experiment stations of New York and Massachusetts whereby their 

 representatives sent samples of the various stock foods collected by 

 them to this Bureau. Several hundred samples were sent and upon 

 receipt were carefully bottled and corked. If they contained an 

 excessive amount of moisture, they were dried in bulk before being 

 bottled. A small amount of the original sample was reserved for 

 microscopical examination, the remainder being ground fine, passed 

 through a sieve with circular holes 1 millimeter in diameter, and 

 rebottled. 



7 



