Complex sentence: Her sister Lasthénie Thuillier-Landry (1879--1962) was also a doctor of medicine and founded the Association of Women Physicians ("Association des femmes médecins").
Split into simpler sentences: Her sister Lasthénie Thuillier-Landry (1879--1962) was a doctor of medicine. Thuillier Landry founded the Association of Women Physicians ("Association des femmes médecins").