(2). Fat (or ether extract) is the portion of the food which is dis- 

 solved from the water-free substance by ether, benzine, gasoline, etc. 

 It is a very important componeht of feeding stuffs on account of its high 

 value for the production of fat, energy, and heat. 



(3). Crude fibre is a term applied to a group of substances that are 

 of limited value to the feeder, because not only are they largely indigest- 

 ible, but what is still more important, they often render the rest of the 

 food less digestible by protecting it from the action of digestive fluids. 



(4). Ash is the inorganic portion of feeding stuffs. Some of the 

 foods richest in protein are also rich in ash material, and are, therefore, 

 of high manurial value. The ash is also of great importance in the food 

 of young and growing animals, as it furnishes the constituents fro'm 

 which the bone is built up. 



(5). Soluble carbohydrates (or nitrogen-free-extract) is that portion 

 of the food which is dissolved by boiling it with dilute acids and alkalies. 

 It consists mainly of starches and sugars. When taken into the system 

 nitrogen-free-extract forms fat or is oxidized to produce heat and energy. 



(6). Moisture. However dry a feeding stuff may appear, it always 

 contains a considerable amount of moisture which can be driven out by 

 heat. A high water content in a concentrated feeding-stuff is a decided 

 detriment : first, because it diminishes the percentage of actual food 

 material, and, second, because it causes the food to mould or turn sour 

 sooner than if less moisture were present. 



In addition to the chemical analysis, the samples that we collected 

 were subjected to careful /microscopic examination, so far as time per- 

 mitted. The chemical analysis alone gives valuable information as to 

 the total quantities of important food materials contained in the feeding 

 stuff. But as will be noticed in the following tables, certain by-products 

 vary considerably in composition, according to the character of the sea- 

 son, methods of manufacture, etc., and unless they are decidedly abnor- 

 mal in composition, it is impossible to say with any certainty whether 

 they have been adulterated or not. Since, however, foreign material 

 can be readily shown under the microscope, the combined chemical and 

 microscopic examination is almost certain to detect any adulteration. It 

 is gratiying to know, on account of the importance and wide use made of 

 these materials, that the quality of the samples in most cases examined 

 has been found to be quite up to the average. The only adulterants we 

 were able to detect were particles of flour, whole wheat screenings, and 

 oat bran, which under the conditions of manufacture might be expected 

 to be present. 



The tables which we are about to examine show how great are the 

 differences in composition between different kinds of feeding-stuffs. 

 Take, for example, the percentage of protein in cotton seed meal and 

 compare it with that in corn bran, or even with that of some of the oat 



