792 SALT ANTAGONISM IN STARFISH EGGS 



in the middle lamella, and also for the normal properties of the sur- 

 face protoplasm. 1^ According to Hansteen, pure alkali salt solu- 

 tions attack and alter primarily the lipoid constituents of the cell 

 walls,"" inducing absorption of water and consequent disintegration; 

 and he cites especially the work of Kreftingj^" who obtained from the 

 intercellular substance of brown algae an acid material ("Tang- 

 saure") which forms water-soluble salts with alkali metals and water- 

 insoluble salts with alkali earths (Ca, Sr, Ba), This compound 

 apparently corresponds with the Ca pectinate to which Mangin 

 attributed the cohesive properties of the material composing the 

 middle lamiclla. 



Hansteen's further observation that the presence of Ca salts in 

 culture solutions is highly favorable to the branching of the roots 

 and the growth of root-hairs in seedlings also indicates that Ca 

 compounds are necessary to the formation of the solid structures 

 essential to normal growth. For example, the development of root- 

 hairs is greatly promoted in media containing several times the normal 

 concentration of Ca salts, a result which has recently been confirmed 

 by Wiechmann^i in Hober's laboratory. Wiechmann finds also that 

 strontium, barium and certain heavy metals (Mn, Ni, Co) act 

 similarly to calcium, while magnesium is ineffective. Such data, 

 when considered in relation to those cited above, throw an inter- 

 esting light on the general significance of calcium in the formation 

 of organic structure. Certain properties of the living protoplasmic 

 structures, such as rigidity, water-insolubility and impermeability 

 to water-soluble substances, seem to require the presence of calcium 

 compounds.22 The rapid alteration of the superficial protoplasmic 



^^ Hansteen, B., Jahrh. wiss. Boi., 1910, xlvii, 374. 



=« Hansteen, B., Jahrb. wiss. Bot., 1913-14, liii, 574. 



^^ Wiechmann, E., Arch. gcs. Physiol., 1920, clxxxii, 99. 



^^ The general view that the presence of water-insoluble materials in the plasma 

 membranes (formed from inorganic salts present) is responsible for their pecu- 

 liar osmotic properties is by no means a new one, having apparently first been 

 suggested by Traube in 1867 on the basis of his work with precipitation mem- 

 branes. Recently the subject has been reviewed by Meigs (Meigs, E. B., Am. 

 J. Physiol., 1915, xxxviii, 456), who has studied the effects of impregnating col- 

 loidal membranes with various inorganic precipitates. Ele finds that membranes 

 made by precipitating Ca and Mg phosphates in thin sheets of celloidin show 



