Hydron compounds are hydrophilic (ionic) solutes. Pure lipid bilayers are generally permeable only to small, uncharged solutes. Bicarbonate ions constitute 48% of river water solutes but only 0.14% for seawater. Transport of soil solutes is termed leaching. In 1889 Hamburger used hemolysis of erythrocytes to determine the permeability of various solutes. Gaseous solutes exhibit more complex behavior with temperature. Examples of such solutes are noble gases and osmium tetroxide. Body fluids are examples for complex liquid solutions, containing many solutes. Mixtures of solutes can achieve similar effects. The cell takes in surrounding fluids, including all solutes present. Thus the stoichiometry of the transported solutes is 1Na&colon;1K&colon;2Cl. They also act as a semi-permeable interface for the exchange of water and solutes. Thixotropy arises because particles or structured solutes require time to organize. This consists of specific transport of solutes across the epithelial cells. The plasma contains 91.5% water, 7% proteins and 1.5% other solutes.