12 The Bulletin". 



of phosphates, sulphates, chlorides and carbonates. The constituents 

 of the ash furnish the material for the bony structure of animals 

 and is used to only a small extent in the tissues and organs. 



NITROGEN-FREE EXTRACT. 



The term nitrogen-free extract includes the non-nitrogenous con- 

 stituents of feeds. The principal classes of substances included in 

 this term are the sugars, starch, organic acids, pentosans, etc. In 

 the ordinary feed analysis the nitrogen-free extract is determined by 

 difference ; the sum of the percentages of protein, fats, fiber, moisture 

 and ash is subtracted from 100, and the remainder considered as 

 nitrogen-free extract. 



CARBOHYDRATES. 



The term carbohydrates includes the nitrogen-free extract and the 

 crude fiber. In publishing the analyses the nitrogen-free extract and 

 the crude fiber are reported separately. To get the per cent of 

 carbohydrates in a feed it is only necessary to add the percentages 

 of these two constituents. 



The percentage of carbohydrates as stated in the manufacturer's 

 guarantee should be, as above stated, the sum of the per cent of 

 nitrogen-free extract and the per cent of crude fiber. 



The following classification will give a clearer understanding 

 of the facts presented above : 



-r> 4. ■ /at o ok\ f True proteins. 

 Protein (JM x 6.25) { A . / , 



v J ( Amido compounds. 



^ 1 Waxes, resins, organic acids, chlorophyl, etc. 



, „. „ f Sugars, 



Carbohydrates j f^^ee extract. J gtarch? 



1 Crude fiber. ^ Pentosan8| etc . 



MICROSCOPIC ANALYSIS OF FEEDS. 



In addition to the regular chemical analysis, all the feed samples 

 are examined microscopically. This is the final test of their purity. 



The chemical analysis shows the percentage amounts of the 

 nutritive constituents of the feed, but it gives no idea of the source 

 from which they are derived, and as the protein and fat are more 

 digestible and hence more valuable in some classes of feeds than in 

 others it is very important to know just what substances go to make 

 up the feed. The microscopic examination is the only way this can 

 be done with any degree of accuracy. 



The chief use of the microscope in feed analysis is in the detection 

 of adulterants and in the detection of the use of spoiled or low-grade 

 seeds. Many feeds are now put on the market in finely ground con- 



