VRIES, HUGO DE. - DISCOVERING PLASMOLYSIS.

Sur la perméabilité du Protoplasma des Betteraves rouges.

La Haye, Nijhoff, 1871. Uncut in orig. printed wrappers. Frontwrapper frayed at edges and with some nicks. In "Archives Néerlandaises des Science Exactes et Naturelles.", Tome 6. II,VIII,483,(1) pp. a. 10 lithographed plates, some in colour. De Vries' paper: pp. 117-126. Internally clean and fine, partly unopened.

First appearance of this importent paper on osmosis, in which De Vries gave the name of 'PLASMOLYSIS" to a chemical concentration of the cytoplasm and linked it with the increased osmotic pressure outside the cell. he also introduces the concept "isotronic", denoting the ration of concentrations, the 'isotronic coefficient'.

"In 1871 he was studying the changes induced in fragments of beetroot immersed in various solutions. The sugar and the cytoplasmic pigment never entered the bath. In contrast, if the concentration of cane sugar or sodium chloride in the external liquid were raised, the cytoplasm contracted, returning to its normal volume when exposed to pure ayer. The impermeability of the cell wall to cane sugar and sodium chloride and the ready passage of water through it was thus established. De Vries gave the name of plasmolysis to this concentration.."

Order-nr.: 45566