34 



out a trace of lime.^ Tliese 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 grams 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 

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



Thus far the only plants which have been proved positively to 

 develop without lime salts are lower forms of algse and fungi (p. 44). 



Like Boehm, Schimper observed an abnormal accumulation of starch 

 where there was a deficiency of lime, but he declares this to be a mere 

 secondary pathological phenomenon, and pointed out that even leaves 

 which are packed with starch may die. This, however, can not be 

 regarded as a refutation of Boehm's views. In order to render starch 

 available for respiration it must be saccharified. In Schimper's case a 

 failure to produce diastase might adequately account for the result. 

 Other discrepancies between the obsei^vations of several authors may 

 have their origin in the different lime content of the seeds used for the 

 experiment. 



Kaumer^ agrees with Boehm in ascribing to the lime the function of 

 aiding in the growth and solidification of the cell walls, but he does not 

 agree with his other views. However, his reason for believing that lime 

 has nothing to do with the transportation of starch is not convincing 

 Certainly, the mere chemical jDrocess of forming starch from sugar 

 does not require lime, but the production of the plastids — the indis- 

 pensable apparatus for starch formation — may require it. 



Holzner's view'^ that lime salts aid in the assimilation of sulphuric 

 and phosphoric acids is very improbable, since his hypothesis would 

 require the forDiation of oxalic acid in every protein-producing cell — a 

 condition which is not realized ; and, moreover, the assimilation of these 

 acids also takes place in fungi in the absence of every trace of lime salts. 

 Finally, Hornberger^ and others have objected to this view as not 

 agreeing with their observations. 



1 Boehm's hypotliesis was entirely misconstrued by one author, who believed he had 

 refuted it by showing that the migrating sugar is not bound to lime — a fact that 

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

 bonic acid. 



^Forstlich. Naturw. Zeitschr., 1892, p. 6, and 1893, p. 215. 



^Landwirtsch. Vers. Stat., 1883, Vol. XXIX, p. 271. 



•1 Flora, 1867, p. 497. 



s^andw. Jahrb., 1882, Vol. XI, p. 455. 



