A milky, product excreted from the latex canals of a variety of plant species that contain cauotchouc. Latex is composed of 25-35% caoutchouc, 60-75% water, 2% protein, 2% resin, 1.5% sugar & 1% ash. rubber is made by the removal of water from latex.(From Concise Encyclopedia biochemistry and molecular biology, 3rd ed). Hevein proteins are responsible for latex hypersensitivity. Latexes are used as inert vehicles to carry antibodies or antigens in latex fixation tests.