The absorption of oxygen and the elimination of carbon dioxide in the lungs take place by diffusion alone. There is no trustworthy evidence of any regulation of this process on the part of the organism.
August KroghIn man, the mechanical breathing is essential to life, and it is one of the old tests for death to see whether these movements have ceased completely.
August KroghWe may fondly imagine that we are impartial seekers after truth, but with a few exceptions, to which I know that I do not belong, we are influenced-and sometimes strongly-by our personal bias; and we give our best thoughts to those ideas which we have to defend.
August Krogh