65 



By the method of Carius — that is, heating iu sealed tubes with fuui- 

 ing nitric acid and silver nitrate — 



(1) 0.2327 gram of leaves and blossoms gave 0.0310 gram AgCl, 

 equivalent to 5.43 per cent of sodium chloride. 



(2) 1.0750 grams of leaves and blossoms gave 0.1432 gram AgCl, 

 equivalent to 5.43 per cent of sodium chloride. 



From these results it would appear that the plant contains chlorine, 

 but, within the limits of experimental error, all the chlorine is present 

 as sodium chloride, Avhich can be leached out with w^ater at ordinary 

 temperatures. This is probably true of the major part of the sul- 

 phates also, although this was not slKnvn quantitativel^^ A striking 

 feature is the much larger amount of ash from the leaves and blossoms 

 than from the stems and the markedly larger percentage of the alkali 

 salts in the ash of the former. The idea suggests itself that possibly 

 this plant takes up and stores the salts and holds them as such 

 until it is ready to use such part of them as it needs. ^ On the other 

 hand, it may be, for all that we now know, that these salts are 

 present as described only because the i)lants can not prevent their 

 accumulation, and, so far from being an inherent feature of the i3lant's 

 econom}', it may be a most undesirable accident due to their peculiar 

 environment, but an accident in spite of which these particular i^lants 

 are able to survive.- But, as Schimper ■ has pointed out, this can not 

 be true in all cases, as evidenced by the fact that halophilous i)laiits 

 show a tendency to take up more salts than nonhalophilous species, 

 even when grown in nonsaline soils. 



None of the chlorine, apparent^, was in organic combination, this 



'Schimper [Indomalayische Strandflora. p. 12 (1891); Pflanzen-Geographie, 

 p. 99 (189S)] has expressed the opinion that halophytes thrive on salty soils 

 because of a peculiar physiological structure which enables them to reduce to a 

 minimum the evaporation from their leaves and, in consequence, the absorption 

 of the salt solutions in the soil through their roots. The salt content of their sap 

 is thus ke;)t below a certain concentration, although this concentration may. 

 and often does, greatly exceed that which would be determined by "osmotic 

 equilibrium." 



Stahl [Hot. Zeitung, p. 139 (1894)] observes that only a few species, such aa 

 Reaumuria Jiirtella, described by Volkens [Die Flora der AegyptisL-h-Arabischen 

 Wliste, p. 27 (1887)]. are known to be able to free themselves from the salt. 



Diels [Jahrb. fiir wiss. Botanique, 32, 31G (1898)] objects that Stahl experimented 

 with cultivated p'.ants and that the retarded root action noted by Schimper does 

 not take place under natural conditions, and that, as a matter of fact, and probably 

 through the agency of malic acid, most, if not all. the halophytes rid themselves of 

 an excess of chloride. Dial's methods of experiment, as well as the conclusions 

 which he draws from his own premises, are criticized by W. Beneke, Jahrb. fur 

 wiss. Botanique 36, 179 (1901). 



Directly bearing upon this hypothesis is an observation by Detmer [Bot. Zeitung, 

 42, 791 (1884)] that "organic acids under the condition prevailing for the vegetable 

 organism are in a position-to decompose chlorides with a formation of free hydro- 

 chloric acid." See also, Osborne, Report Conn. Ag. Ex. St., 1900, p. 411. 



- Contejean, Geog. Bot., p. 71. 

 Schimper. Pflanzengeographie, p. 101 (1898). 



8287— No. 71—02 5 



