204 HOW CROPS GROW. 



ditions. It now remains to attempt in some degree the 

 combination of these sketches into a panoramic picture 

 to give an idea of the composition of the plant at the 

 successive steps of its development. We shall thus gain 

 some insight into the rate and manner of its growth, and 

 acquire data that have an important bearing on the requi- 

 sites for its perfect nutrition. For this purpose we need 

 to study not only the relative (percentage) composition 

 of the plant and of its parts at various stages of its exist- 

 ence, but we must also inform ourselves as to the total 

 quantities of each ingredient at these periods. 



We shall select from the data at hand those which illus- 

 trate the composition of the oat-plant. Not only the ash- 

 ingredients, but also the organic constituents, will be no- 

 ticed so far our information and space permit. 



The Composition and Growth of the Oat-Plant may 



be studied as a type of an important class of agricultural 

 plants, viz. : the annual cereals plants which complete 

 their existence in one summer, and which yield a large 

 quantity of nutritious seeds the most valuable result of 

 culture. The oat-plant was first studied in its various 

 parts and at different times of development by Prof. John 

 Pitkin Norton, of Yale College. His laborious research 

 published in 1846, (Trans. Highland andAg. Soc. 1845-T, 

 also Am. Jour, of Sci. and Arts, Vol. 3, 1847,) was the 

 first step in advance of the single and disconnected anal- 

 yses which had previously been the only data of the agri- 

 cultural physiologist. For several reasons, however, the 

 work of Norton was imperfect. The analytical methods 

 employed by him, though the best in use at that day, and 

 handled by him with great skill, were not adapted to fur- 

 nish results trustworthy in all particulars. Fourteen years 

 later, Arendt,* at Moeckern, and Bretschneider,f at Saarau, 



* Wachsthumsverhyitnisse der Haferpflanze, Jour, fur Prakt. CJiem., 76, 193. 

 t Das Wacftsthum der Haferpflanze^ Leipzig. !&>!). 



