33 



plants "Town in very faint li^ht and with normal control plants. The 

 plants were grown in i>nritie<I (jiiartz sand and watered with culture 

 solutions in equal quantities. The culture was terminated after forty- 

 four days, because the plants under violet and green glass began at 

 that time to show signs of approaching death. The analyses of the 

 ash gave some interesting results, especially as regards the lime con- 

 tent, and are as follows: 



Comparative amounts of maf/nesia, livie, and poiasaa per thousand pari h of dri/ matter of 

 normal and etiolated jjlants and plants grown under different colored glass. 



Condition of plant. 



Normal 



Etiolated 



Under jxreeu glass. . 

 Under violet glass . 



Under red glass 



Under blue glass... 

 Under yellow glass 



Magnesia. Lime. Potassa. 



Per cent. Per cent. 

 32.1 i 48.5 



IS. 4 

 18. S 

 20.2 

 24.3 

 30.2 



44.9 

 56.5 

 45.6 

 56.5 

 61.1 



30.3 53.2 



The amount of phosphoric acid varied only from 16.7 to 20.5 per cent. 

 The etiolated plants and those under green glass contained the smallest 

 amount of lime, and a certain relation of the lime content to assimila- 

 tion or rather to the x)lastids is evident. 



VIEWS ON THE FUNCTIONS OF LniE SALTS. 



Boehm ' observed irregularities in the transportation of starch when 

 lime salts were absent in the culture solutions. The plants (Phaseolus 

 multifiorus) recovered ^ on the addition of calcium salts, while on the 

 other hand the addition of magnesium salts hastened their death. The 

 irregularity of behavior in the absence of lime consisted in the accumu- 

 lation of starch in the pith and bark of the lower part of the stem. The 

 death of the affected ])lants commenced generally in the upper parts of 

 the stems and gradually spread to the lower parts. Boehm further 

 attributed to the lime a function in the formation of the cell wall. He 

 says: "In order to form the cell wall from starch and sugar, lime is 

 just as important as for the formation of the bone. The lime forms the 

 skeleton of the cell wall." One author,^ however, claims that Boehm's 

 inferences are not justified, as he had studied only one case. Some 

 authors have e\^n gone so far as to assert that lime ^alts are by no 

 means required for every part of a plant, and one author concluded that 

 leaves of Tradescantia may be raised without lime, another that the 

 young wood is free of lime, and a third that Fucus may be found with- 



'Ber. Atad. d. Wissenach., Wien, 1875. 



- The addition of calcium chlorid, however, did not prevent death, prohably owing 

 to the liberation of hydrochloric acid when the attempt is made by the plant to 

 assimilate the lime from this salt. 



^Liebenberg, Ber. Akad. d. Wiss., Wien, 1881. 

 7478— No. 18 3 



