The model of the speech circuit proposed by Ferdinand de Saussure in "Course in General Linguistics" (1966 [1916]). A conversation is an exchange of vocalized mental signs. The drawing uses the oak clipart by rg1024 http://www.openclipart.org/detail/colored-oak-tree-by-rg1024
Symbol for the sudden infant death syndrome. Babys sharing their home with a smoker have a higher risk of dying from SIDS.
Part of a series about the adverse effects of smoking.