334 HOW CKOPS GROW. 



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



and handled by him with great skill, were not adapted to 



furnish results trustworthy in all particulars. Fourteen 



yeats later, Arendt* at Moeckern, and Bretsbhneiderf at 



Saarau, in Germany, at the same time, but independently. 



of each other, resumed the subject, and to their labors 



the subjoined figares and conclusions are due. 



Here follows a statement of the Periods at which the 



plants were taken for analysis : 



[stiU closed. 

 lot varinri 1 June 18, Aieiidt — Three lower leaves unfolded, two upper 

 xs\, ireiiou ( „ jg^ Bretsohneider— Four to five leaves developed. 

 „ J v„ri„ J 1 June 30, (12 days), Aiendt— Shortly hefore full heading. 

 ^a r-eiioa j „ 29, (10 days), Bretschneider— The plants were headed. 

 5/1 varin^ X July 10, (10 days), Arendt— Immediately after bloom. 

 6a i-erioaj „ s, ( 9 days), Bretsohneider— Full bloom, 

 dtj. Vorin^ I Jily 21, (11 days), Arendt— Beginning to ripen. 

 *injrenoaj .. 23, (20 days), Bretschneider— " 

 >ith ppvinrl I J^ly 31, (10 days), Arendt— Fully ripe, 

 om ±-eiion I ^yg g^ ^ g days), Bretsohneider— Fully ripe. 



It will be seen that the periods, though differing some- 

 what as to time, correspond almost perfectly in regard to 

 the development of the plants. It must be mentioned 

 that Arendt carefully selected luxuriant plants of equal 

 size, so as to analyze a uniform material (see p. 171), 

 and took no account of the yield of a given surface of soil. 

 Bretsclineider, on the other hand, examined the entire 

 produce of a square rod. The former procedure is best 

 adapted to study the composition of the well-nourished 

 individual plant; the latter gives a truer view of the crop. 



The unlike character of the material as just indicated" 

 is but one of the various causes which might render the 

 two series of observations discrepant. Thus, differences 

 in soil, weather and seeding, would necessarily influence 

 the relative as well as the absolute development of the two 

 crops. The results are, notwithstanding, strikingly ac- 

 cordant in many particulars. In all cases the roots were 

 not and could not be included in the investigation, as it 

 is impossible to free them from adhering soil. 



* Das WacJtsthUTn dnv Hn-ferpjlanze^ ZHpzi^j, 1859, 



t Wachsthumsverhaitnisse der Haferpflanze, Jour, filr Prakt. Chem., 76, 

 193. 



