In 1936, Vollard commissioned another book from Picasso, this time on the theme of Buffon's mammoth Histoire Naturelle of 1749 to 1804. Originally made up of 44 volumes, Buffon's treatise on the physical, anatomical, and physiological traits of all the animals had to be drastically cut. Picasso chose to illustrate only 31 animals from the horse, considered the most useful animal, to the flea. He employed the new technique of lift-ground aquatint which offered him an extraordinary array of textures and tones. In these highly evocative prints, Picasso expertly captures the essence of each animal, in this case, the gaukiness of a sprinting ostrich.