Wolff, against prevailing orthodoxy, proposed that organisms grew from cells, rather than pre-existing in miniature form: conventional views of animal and plant growth date from his work. Little is known of his youth. He and Haller were in constant contact when he was researching the growth of embryos; although Haller argued publicly against Wolff’s ideas, they greatly interested him, his mind perhaps more open than he acknowledged. Wolff had difficulty finding an academic position until Euler helped him to one at St Petersburg. His relations with other colleagues there — Gmelin, Müller, Lomonosov, etc. — are unclear.