

FIG. 12. A drop of sea water joined by a canal with a drop of distilled water. The 

 density of the sea water is being gradually increased in the successive figures by 

 the dissolution of grains of salt placed at one edge. As the solution thickens, the 

 organisms (marine Anophrys, represented by dots) retreat towards the distilled 

 water. (From MASSART, '91.) 



such that they are repelled by either hyperisotonic or hypiso- 

 tonic solutions ; only in a certain concentration do they come 

 to rest. We may speak of these organisms as attuned to 

 this concentration. Different organisms are attuned to dif- 

 ferent concentrations, and there can be no doubt that the 

 degree of concentration to which they are attuned is deter- 

 mined by the past experience of the organisms, as the facts 

 of acclimatization indicate. 



LITERATURE 



BERT, P. '66. Note sur la mort des poissons de mer dans Peau douce. 



Mem. Soc. Sci. phys. et nat. Bordeaux. IV, 47-49. 

 '71. Sur les phenomenes et les causes de la mort des animaux d'eau 



douce que Ton plonge dans 1'eau de mer. Comp. Rend. LXXTEI, 



382-385 ; 464-467. Aug. 1871. 

 '73. La mort des animaux d'eau douce que 1'on immerge dans 1'eau de 



mer. C. R. Soc. de Biol., Paris. XXIII, 59-61. 

 '83. Sur la cause de la mort des animaux d'eau douce qu'on plonge dans 



1'eau de mer et reciproquement. Comp. Rend. XCVII, 133-136. 



16 July, 1883. 

 BEUDANT, F. S. '16. Memoire sur la possibilite de faire vivre des Mol- 



lusques fluviatiles dans les eaux salines, etc. Jour, de Phys. LXXXIII, 



268-284. 1816. 

 BL T TSCHLI, O. '92. Untersuchungen iiber mikroskopische Schaume und das 



Protoplasma. Leipzig. 232 pp. 1892. 



