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the proportion of this mineral varies as much 

 in wheat-straw as bone does in very lean and 

 very fat swine or cattle. 



A young growing animal, whether a child 

 or a colt, that is kept on food that lacks bone- earth 

 (phosphate of lime), will have soft cartilaginous 

 bones. Just the same as nature cannot substitute 

 iron or any other mineral in the animal system, 

 out of which to form hard, strong bones, so no other 

 mineral in the soil can perform the peculiar function 

 assigned to silica in the vital economy of cereal 

 plants. To protect the living germs in the seeds 

 of wheat, corn, oat, rye, barley, &c., the cuticle 

 or bran of these seeds contains considerable flint. 

 The same is true of chaff. 



The question, then, naturally arises, how is the 

 farmer to increase the quantity of available silica 

 in his soil ? This is a question of the highest 

 practical importance. There are three principal 

 ways in which the object named may be attained. 



First, by keeping less land under the plough- 

 Land in pasture, if well managed, will regain its 

 fertility, and in the process accumulate soluble 

 silica in the surface- soil. In this way, more wheat 

 and surer crops may be made by cultivating a 

 field in wheat two years than four or six. If the 

 field in the meantime be devoted to wool-growing, 

 butter or cheese-making, or to stock-raising, parti- 

 cular care should be observed to make extensive 



