176 ELEMENTARY AGRICULTURAL CHEMISTRY 



milk. According to Lehnxann, the ration for cows should vary 

 in accordance with the following table ; 



Another point of importance in connection with foods is the 

 supply of sufficient mineral matter, lime and phosphates parti- 

 cularly, for the requirements of the animal. Young animals 

 especially are liable to suffer in development should their food 

 be deficient in these constituents. Fortunately many of the 

 concentrated foods — e.g., oil-cakes — valued for their richness in 

 nitrogen and fat, are also rich in ash constituents. Maize and 

 rice are perhaps the worst foods in this respect. 



Recent investigations show that the ratio of basic material 

 to acid radicals in the ash of a food is of much importance. In 

 cereals, for example, the amount of bases (lime and magnesia) 

 is small compared with the amount of phosphoric acid, and 

 there is reason to think that an exclusive cereal diet is not good 

 for horses, &c., and may encourage certain diseases of the bones. 

 From a study of the composition of bones of animals suffering 

 from certain bone diseases, the writer has recently come to the 

 conclusion that the diet of animals should contain at least as 

 much lime as phosphorus pentoxide, or otherwise the proper 

 nutrition of the bones is disturbed. The following table gives 

 the ratio of lime to one of phosphorous pentoxide in certain 

 food-stuffs : 



