I OBSERVE several letters in NATURE, vol. xxiv. pp. 101 and 126, on floating as a means of preventing drowning, but I do not think the last word is yet said on this subject. I fully agree with Dr. Dudgeon that no rules for preventing drowning are of any practical value, and also with Mr. Hill and Dr. Dudgeon that those who can float are the rare exceptions. According to my observation not one in ten, in fact I might say hardly one in 100 even, of good swimmers can float in fresh water in any useful fashion, i.e., lying motionless on the water and breathing easily. The obvious reason is that the human body in the natural condition, i.e., with the lungs half inflated, is specifically heavier than water. Many persons say they can float, but in most cases they either inflate the lungs and hold the breath, or else they make slight movements of the hands.