6 MASSACHUSETTS AGRICULTURE. 



chalk. The necessity for such food is commonly taken for 

 granted, from the fact that lime enters into the composition of 

 the shell of the egg ; so does phosphate of lime enter largely 

 into our hones, and from the law of change, which is continually 

 tearing down and rebuilding our framework, this phosphate is 

 constantly needed : yet no man advocates a bone diet. Many 

 of the molusca have ponderous shells of carbonate of lime to 

 construct, yet it is never conjectured that they digest this in a 

 mineral form. The milk of cows abounds in phosphate of lime, 

 and they must supply the ingredient daily ; yet when the 

 animal is healthy, and her pasturage such that the grasses on 

 which she feeds have their proper proportion of phosphoric 

 acid, who ever knew a cow to crave the phosphate in a mineral 

 form ? The argument from analogy, therefore, fails. It is 

 true, fowls will eat fragments of bone, clam shells, oyster shells 

 and stone, and it is therefore inferred that the lime must be 

 used in the formation of the shell of the egg ; but the male eats 

 this mineral matter as readily, in proportion to the amount of 

 food consumed, as the female. Again, it is urged to give burnt 

 bones ; now the lime that enters into the composition of the 

 shell of the egg, is almost wholly carbonate of lime, but the 

 lime in these burnt bones is almost wholly phosphate of lime. 

 Again, in the pebbles there may not be a particle of lime, and 

 yet they will devour these, and for the same reason. that the 

 fragments of shell are consumed, viz. : to supply that wonderful 

 internal grinding apparatus of theirs with millstones ; and as 

 nature is no bungler in all her works, she has made them good 

 millers by implanting in them a liking for the hardest and 

 most angular fragments. It may here be objected that they 

 readily devour the shells of eggs ; but this apparent exception 

 is readily accounted for, from the large proportion of animal 

 substance remaining on the shell or entering into its com- 

 position. 



If the argument is pursued farther, from a chemical point of 

 view, you will find that there exists in our grains a sufficient 

 proportion of carbonate of lime to answer all the demands of 

 nature in the construction of the shell of the egg. Finally, it 

 is against all the analogy of nature to assume that an animal, 

 with its functions in normal condition, requires any mineral as 



