UTILIZATION OF FOOD 431 



the limbs and spinal column bend, the teeth remain small and 

 loose, and the bones weak. Pigs especially are liable to suffer in 

 this way because the potatoes and cereals fed to them do not con- 

 tain enough lime. 1 Straw and chaff of cereals, the cereal grains, 

 and their by-products, as bran, gluten meal, etc., malt sprouts, 

 molasses, and whey, are poor in lime. The straw and chaff of 

 grains, beet pulp, potato pulp, and molasses are poor in phos- 

 phoric acid. Clovers, meadow hay, and leguminous seeds are 

 rich in lime. Cereal grains, bran, oil cake, flesh, and fish by- 

 products are rich in phosphoric acid. 



When lime is deficient in the feed, it may be supplied as pre- 

 cipitated chalk. Lime and phosphoric acid together may be given 

 in the form of precipitated phosphate of lime or finely ground 

 bone. 



Lecithin 2 appears to stimulate the growth of the bones and 

 body. For example, one guinea pig fed o.io gram lecithin per 

 day, in addition to other food, increased 1,380 grams in 10 weeks; 

 but another pig fed no lecithin, under the same conditions, gained 

 300 grams. 3 



Water. Water lightens the work of chewing, and makes swal- 

 lowing possible. It is indispensable to digestion and absorption 

 of food. The digestive ferments can act only in solution, and 

 the products of digestion can enter the body in dilute solution 

 only. Concentrated solutions cause strong peristaltic move- 

 ments, which end with the ejection of the material. Water also 

 circulates in the blood and secretions, and carries out the ex- 

 creted metabolic products in the urine. It aids to remove an 

 excess of heat from the body by evaporation. One gram of 

 water on being converted from the liquid to the gaseous state 

 takes up 535.9 calories. 



Too little water delays digestion and absorption, and causes 

 the nitrogenous metabolic products to remain in the body longer 

 than usual. The blood gradually thickens, the body temperature 

 is elevated, and the decomposition of fat and albumen con- 



1 See Missouri Bulletin No. 6. 



2 Missouri Bulletin No. 61. 



3 Compt. rendu., 1902, p. 1166. 



