Boy with infantile paralysis, Muybridge motion study, 1880s. Series of photographs showing the movement of a boy with infantile paralysis, or poliomyelitis, affecting his legs. Poliomyelitis is caused by the polio virus. In severe cases the virus infects the central nervous system (CNS) causing inflammation and cell death. Muscles served by the affected nerves are weakened and can be paralysed. These photographs were obtained by English photographer Eadweard J. Muybridge (1830-1904) in his pioneering work documenting the motion of humans and animals. Between 1883 and 1886, Muybridge made more than 100,000 images using his ground-breaking stop-motion photography techniques. In 1885 he partnered with Francis Dercum, chief of the Hospital of the University of Pennsylvania's Dispensary for Nervous Diseases to study the movement of neurological patients. The results were published in 'Animal Locomotion' (1887). This study was published in Volume VIII: Abnormal Movements. Males and Females (nude and semi-nude).