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, (Zrans. Highland and Ag. Soc. 1845-7, 
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,t at Saarau, 
* Wachsthumsverhaltnisse der Hafernfanze, Jour. fir Prakt. Chem., t6, 193. 
+ Das Wachsthum der Haferpflanze, Leipeig. 1859, 
