What did Jan Ingenhousz discover about plants kept in the dark?

Jan Ingenhousz discovered that when plants are kept in the dark, they do not produce the oxygen bubbles associated with photosynthesis.1

Instead, he observed that in darkness, plants release carbon dioxide, a process he described as "damaging" the air. Ingenhousz concluded that while all living parts of a plant respire—thereby releasing carbon dioxide—the amount of oxygen produced by green parts in sunlight far exceeds the amount of carbon dioxide released in the dark. His findings were detailed in his work, Experiments upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and of Injuring It in the Shade and at Night.12