EXPERIMENTAL STUDY. 41 
In this series the cotyledons were attached to the plants when reset, 
and they, together with the nutrients in the solutions, enabled all the 
plants to make same growth. However, without exception, they were 
soon overcome by the noxious influence of magnesia in the absence 
of lime, while those in solutions containing lime preserved a normal 
appearance. 
On August 13a series of cultures were started, using cowpeas 30 
em. high. The plants had been sprouted in clean sawdust, and had 
exhausted the substance stored in the cotyledons. One cubic centi- 
meter of the nutrient solution was added to each bottle, the additional 
nutrients added, and the results are shown in the following table: 
Results of experiments with cowpeas set August 12. 
| August 13. August 20. | August 27. September 6. 
| No. of mei ee 
/ Bettie. Solution. or Condition. | Condition. Condition. 
z 
| a Hee eo > eck. Soe Dejecied ..| Dying --...- Dead. 
17 | MgO as Mg(NOs)o ----| 0.1 | Growing...) Dying ...-. Dead. 
18 | CaO as Ca(NO3)o..----| 0.1 | Growing...) Healthy .... Growth ceased, leaves 
i curling. 
19 f MgO as Mg(NOsz)o ---- 0. 05 Ae ..| Healthy -..| Healthy. 
|, CaO as Ca(NOsg)o...--- 0.05 ) 
oo! pe ee), 8- icsowine. .-| Healthy ...| Healthy. 
|| CaO as Ca(NOsz)o.-.--- 0.1 J 
| oi! NazO as Nags -.---. 0.05 Neroerioe: .-| Healthy -..| Healthy. 
|| CaO as Ca(NOz)o.:.--.| 0.1 JJ 
| MeO as Me(NO3); -..-| 0.1 uaee SCD ying =< 22 Dead. 
|| K,0 as KNO,......... 0.1 
og) MgO as Mg(NO3)2---. 0.1 Oe Ee ..| Healthy -- | Healthy. 
|| CaO as Ca(NOsz)o..----| 0.05 | 
oat MgO as Mg(NOz)o----| 0.1 frei ..| Healthy ...| Healthy. 
| || CaO as Ca(NOsz)o..----| 0.1 | : 
25 j MgO as Mg(NOsz)2-..-; 0.1 feats .-| Healthy ...| Healthy. | 
| | CaO as Ca(NO3)o....-. 0.2 [J 
i y {D 3 a) 
og! MgO as Mg(NOsz)2.-.-/ 0.1 tine =-/} ede ce Dead. 
|| FeO as FeSQ,.......-. 0.02 } | leaves. |} 
MgO as Mg(NOz)o...-, 0.1 |] , : 
or! hate Growing...) Dying ....- Dead. 
|| NasO as NaNOg....--. "AO 9 ae teas ae ' 3 
| | 
| 28 | MgO as MgSQ,y.......- 0.1 | Growing...| Dying ....- _ Dead. 
| 
In these experiments, with lime and magnesia in solutions, the 
results under like conditions were very uniform throughout. When 
the death of the plant ensued there was first noted a shrinkage of the 
leaf, followed by a browning of the root system and a stoppage in the 
development. The growth of root hairs, especially, was hindered. As 
plants sprouted in solid media and transferred to water cultures throw 
out a different kind of root hair in order to adapt themselves to the new 
media, it is probable that the first injury in the magnesia solution lies 
in the deterrent action of that element upon this process. 
While the action of magnesia in the absence of lime proved poison- 
ous, the absence of magnesia with lime present when a certain point 
