FUNCTIONS OF LIME SALTS. 41 



The amount of phosphoric acid varied only from 16. 7 to 20.5 percent. 

 The etiolated plants and those under green glass contained the smallest 

 amount of lime, the beneficial rays having- been cut off by the glass 

 in the latter case. 



VIEWS ON THE FUNCTIONS OF LIME SALTS. 



Boehm" observed irregularities in the transportation of starch when 

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

 multiflorus) 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 plants 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 even gone so far as to assert that lime salts arc 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 Fuous may be found with- 

 out a trace of lime. d These statements, however, were based princi- 

 pally on microscopical tests and could not be upheld. Some new leaves 

 of Tradescantia may indeed develop completely when the branches are 

 kept in distilled water, since, as the writer has observed, the nodes con- 

 tain a considerable amount of stored-up lime. As to the assertion in 

 regard to young wood, Weber's analyses' have revealed a considerable 

 amount of lime in its ash. For example, 1 cubic meter (Festmeter) of 

 the wood of Larix was found to contain 700 grams of lime, of which 

 112.4 grains belonged to the young wood. The young wood of Fagus 

 contained about 29 per cent of lime in the ash. As regards the Fucus 

 referred to above, it was only its cell sap that proved to be free from 

 lime, while an examination of the organized parts revealed lime in them. 



«Ber. Akad. d. Wise., Wien, 1875. 



6 The addition of calcium chlorid, however, did not prevent death, probably owing 

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

 assimilate the lime from this salt. 



c Liebenberg, Ber. Akad. d. Wiss., Wien, 1881. Cf. also D6herain and Demoussy, 

 Compt. Kend.. 1901, vol. 132, p. 523. 



d Boehm's hypothesis was entirely misconstrued by one author, who believed he 

 had refuted it by showing that the ryigrating sugar is not bound to lime — a fad that 

 might have been foreseen, as such a compound would be decomposed quickly by car- 

 bonic acid. 



^Forstlieh. Naturw. Zeitschr., 1892, p. <>, and 1893, p. '-'15. 



