668 ANNUAL REPORT OF THE Off, Doc. 



course of a few moments, extract from the soil precisely those kinds 

 of compounds and in precisely the quantities which a growing crop 

 will abstract in an ordinary season of growth, you will better com- 

 prehend his dini( iilties. Chemical analysis has enabled us to dis- 

 cover those cases where soils are exceedingly deficient in an availa- 

 ble form of some one or more plant food constituents. The more re- 

 fined methods have also, in a number of cases, enabled us to predict, 

 with a fair degree of success, the action of certain classes of fertili- 

 zing materials upon them; but in this field much still remains to be 

 done before the hoped for result is attained. The past century has 

 seen the birth and (he great development of the commercial fertili- 

 zer, a form of coucentraird plant food, designed to supplement the 

 available supply in the soil of some particular plant nutrient; and 

 chemical investigation has done much to reduce the cost of the 

 preparation of these fertilizers a«d to utilize in their manufacture a 

 great deal of material which w^as heretofore wasted or lay neglected 

 in the crust of the earth. It is quite possible now, as a result of 

 these advances in fertilizer manufacture, to put into a soil whose 

 texture fits it for the intensive culture of a high-priced crop, such 

 as early truck, a very large proportion of the plant food which the 

 plant requires and do this with economical results. 



In the domain of animal life, the investigations of the agricultural 

 chemist have brought us still nearer to a perfect control of the kind 

 and amount of product, whether of milk or of meat; so that, to-day 

 the practical farmer has accepted, because he has found them to be 

 applicable to his practice, rules for the compounding of his rations 

 that have been formulated on the basis of the investigations of the 

 chemical laboratory upon the operations of the stable. Yet despite 

 this very material advance, we note that much remains to be done in 

 this field. Great numbers of plant substances are grouped under 

 a few broad heads and treated as though their nutritive and dietetic 

 effects were precisely the same. Investigations of recent years have 

 done mi:ch to show that still finer distinctions should be drawn be- 

 tw'een the components of foods than has yet been done, and thou- 

 sands of experiments must be made under more refined methods of 

 operation before the scientific facts and their practical relations 

 can be discovered and formulated. 



The work of the chemist has, however, not stopped at this point, 

 but much of his energy has been devoted to the improvement of the 

 processes of harvesting, curing and storing of the vegetable products, 

 and to the development of manufacturing processes which depend 

 upon the products of the farm for their raw materials. The exact 

 control now practiced in the manufactnro of sugar by w'hich the 

 waste of nearly one-half the crystalline product in the cane that 

 was prevalent fifty years ago, has been for the most part overcome; 

 and it is due to such investigation that the more exact manufacture 



