366 



K. ASo. 



The same proportion is obtained from numerous analyses 

 when the average of the lime and magnesia content of barley 

 straw is taken. 



Cultures of Soy-beans in Ihe Presence 

 of all Mineral Nutrients. 



On March 15th, shoots of the soy-bean 7 — 11 cm. high, 

 were placed (two shoots in each case) in the same solutions 

 as had served in the experiment with barley just described. 

 Five days afterwards the cotyledons were removed 1 in order to 

 exclude the further influence of the reserve mineral matter. 



After four weeks a decisive difference in the development 

 was observed which became now more marked day by day, and 

 by May 7th, most of the leaves in (a), (b), and (c), showed a sickly 

 appearance In (a) the uppermost leaves had turned white, 

 retaining some green only along the chief veins while in (b) and 

 (c), the normal green had changed to a yellowish color. In 

 regard however not only to the color, but also to the size, the 

 balance was much in favor of the solutions (d) and (e). 



During the first two weeks, the plants in (b) and (c) had 

 made a better showing than those in the other solutions, but 

 gradually as the further development of new leaves required 

 more lime the balance changed in favor of the solutions (d) and 

 (e). On April 29th, the solutions were renewed and on May 

 13th, a photograph was taken, which is reproduced on plate 

 XLIY. This shows the differences in development very plainly. 



A very unwelcome feature, was noticed in the first traces 

 of a parasitic fungus on some leaves in (b) and (c), but this 

 trouble set in when the experiment had already decided the 

 question at issue. At this time the pale color of the leaves in 

 (a), had already clearly proved the imperfect formation of the 

 chloroplasts under the influence of an excess of magnesium 

 nitrate. 



On May 28th, the plants were weighed in the fresh state 

 after the water adhering to the roots had been removed with 

 filter paper, and the total length of the stems was measured. 

 The rather slow development of these shoots even in the most 



1 The average weight of one pair of cotyledons was, in the fresh state = o.7o,6 grm. ; 

 dried at ioo° = o.I3I grm. 



