No man or woman will ever forget the time when some child lies sick of a disease that threatens its life.
 Theodore Roosevelt, Theodore Roosevelt; an Autobiography (1913). copy citation

Context

“the water fairly foamed with vigorously kicking little legs; and then there was always a moment of interest while I counted, so as to be sure that the number of heads that came up corresponded with the number of children who had gone down. No man or woman will ever forget the time when some child lies sick of a disease that threatens its life. Moreover, much less serious sickness is unpleasant enough at the time. Looking back, however, there are elements of comedy in certain of the less serious cases. I well remember one such instance which occurred when we were living in Washington, in a small house, with barely enough room for everybody when all the chinks were filled.” source