Abstract
CLAUDE BERNARD'S postulation concerning the
presence of a constant internal environment in the
higher animals serves admirably to explain the
nature of this essay. Speaking of this environment
he said, "The constancy of the environment presupposes
such a perfection of the organism that at every
moment external variations are compensated and
equilibriated".
This essay attempts to describe the nature of
those substances responsible for the maintenance
of a constant hydrogen ion concentration in the
body fluids, or, in other words, the buffers in
these fluids. A buffer is a substance capable of
producing either H or OH ions, but which is so
weakly ionised in solution that changes in its concentration
make very little difference to the total
amount of whichever ion it produces. Of such a
nature are the salts of weak acids and bases, or
mixtures of weak acids or bases with their salts,
and the proteins. How these effect their buffering
action is best demonstrated by an example of one in
action. Supposing we add to the buffer NaA the
strong acid HC1. The result is: HCl + NaA= NaCl + HA
This HA is so weakly dissociated that the pH of the
solution shows little change.
