IN ANOTHER part of this symposium the terms acid, base, and buffer have been defined. For purposes of this discussion we will define a buffer as a substance or substances which minimize the hydrogen ion change in a solution when hydrogen ions are added or removed. A weak acid and its salt or a weak base and its salt serve this function and are the substances usually thought of as buffers. The buffering mechanisms utilized by the body to minimize hydrogen ion change in body fluids in the face of invasions of acids or bases are the subject of this paper.
The buffers that minimize hydrogen ion change in the transport of carbon dioxide and those that minimize the change produced when acids or bases other than H2CO3 or bicarbonate ion are introduced are often confused. This confusion arises partly from the fact that the bicarbonate system