62 FERTILITY AND I'ERTIUZER HINTS 



combs and similar articles. In the raw state they are extremely 

 hard to grind and are not valuable in this form because they 

 decay too slowly to supply plant food with any degree of rapidity. 



Fig. b.—\ stock yards scene where tankage, blood, liorn and hoof meal and 

 similar fertilizer products are saved. 



When steamed and pulverized they become high grade products 

 as mentioned in the previous chapter. 



Wool waste, shoddies, etc., taken collectively is the term ap- 

 plied to any waste from silk or wool manufacturing which is no 

 longer profitable for making cloth. It is slow to decay and is 

 rather undesirable as fertilizer. It is often coarse and bulky and 

 hard to mix in a manufactured fertilizer or to distribute evenly 

 when applied to the soil.* 



It is sometimes treated with superheated steam, the liquid 

 evaporated to dryness and the product ground, or else it may be 

 acidulated with sulphuric acid for a long time (2 months) to 



