4 THE SCIENTIFIC FEEDING OF ANIMALS 



placed in a drying glass (Erlenmeyer flask) and dried at 102 to 105" C. until the 

 weight has become constant. This usually requires from three to five hours. The 

 loss in weight represents the moisture content. In the case of succulent material, 

 carefully weighed portions may be cut into small pieces, thoroughly dried, then 

 ground in a mill, as above, and desiccated in the same manner. 

 II. Salts, Mineral Matter, or Ash 



The mineral matter (sahs, ash or inorganic matter) is what remains 

 after destruction of the dry organic matter by burning. 



The ash obtained from the weighed portion of the air-dried substance by the 

 usual method of burning does not, however, represent the exact amount of rnineral 

 matter. On the one hand, small quantities of inorganic combinations of chlorin and 

 sulphur are lost by volatilization ; on the other hand carbonic, sulphuric and phos- 

 phoric acids are formed from the organic substance (e.g., the albuminous portions) 

 during the process of combustion, combine chemically with potassium, sodium, lime 

 and magnesia, and remain as a residue in the ash. Thus, when absolute accuracy 

 is not essential, we merely determine the weight of the white (crude) ash, which 

 may contain besides carbon dioxid, small amounts of charcoal and silica (or sand). 

 For accurate results it is necessary to determine the amount of CO2 which entered 

 into combination with mineral matter during combustion, and subtract the amount, 

 with that of the silica, from the weight of the ash. (For further details see Bey- 

 thien, Hartwig and Klimmer), 



The principal mineral constituents of feeding stuffs are potash, sodium, 

 calcium, magnesium, iron, aluminum, manganese, phosphoric acid, sul- 

 phuric acid, silicic acid and chlorin. In addition to these there are pres- 

 ent occasionally and in small quantities or traces lithium, barium, rubid- 

 ium, caesium, iodin, bromin, etc. Under exceptional conditions there may 

 be present lead, copper, arsenic, zinc. With reference to these poison- 

 ous mineral constituents, see Klimmer, Veterinary Hygiene. The mineral 

 elements appear in the composition of plants, in part as inorganic salts, 

 in part as organic combinations. The latter are especially valuable and 

 important in the process of nutrition on accoimt of the facility with which 

 they are absorbed into the tissues. 



The amount and character of the mineral matter in the different feed- 

 ing stuffs varies according to the species of plant, the part of the plant in 

 question, as well as soil, fertility and weather conditions. Methods of 

 curing and commercial processes often affect the proportion to a con- 

 siderable extent. The importance of salts or mineral matter in nutrition 

 as well as in the conservation of health and efficiency of our domestic 

 animals is frequently not sufficiently appreciated. Special consideration 

 should be given to the mineral constituents of feeding rations, especially 

 where the feeding is more or less artificial. Feeding stuffs do not always 

 contain a sufficient amount of mineral matter, especially of lime, phos- 

 phoric acid and sodium chlorid. Less frequently they are deficient in 

 potash. In dry seasons plants take up less mineral matter than in wet 

 seasons for the reason that the necessary solvent, water, is absent. Soils 

 deficient in these salts produce plants similarly deficient, etc. 



In regard to the occurrence of the nutrient salts in feeding stuffs, the 

 following should be noted : 



Potash is abundant in so-called root croops (potatoes, artichokes, beets 

 and beet molasses), in the seeds and straw of leguminous plants (excepting 

 lupines), also in the hulls of beans, in young forage plants (aftermath), 



