Heard any bad knees lately?

Knee‐joint problems of various kinds seem to affect almost everyone sooner or later, highly priced football players and ordinary mortals alike. A group at the University of Akron have been listening to the clicking and scraping noises of defective knees, and they reported to the 91st Meeting of the Acoustical Society of America, in Washington last April, on what they had heard. The photograph shows Larry Zavodney, a graduate student in mechanical engineering, with a cow's knee joint that he and Mamerto L. Chu are using for in vitro studies of these sounds.