Complex sentence: From about 1853 Lewes's writings show that he was occupying himself with scientific and more particularly biological work, though he always showed a distinctly scientific bent in his writings, though he had not had technical training.
Split into simpler sentences: From about 1853 Lewes's writings show that he was occupying himself with scientific and more particularly biological work. He always showed a distinctly scientific bent in his writings, though he had not had technical training.