Note 4 — Chapter I · The Impulses of Attachment
Reading edition
Wilfred Trotter: The Instincts of the Herd in Peace and War. Other writers have emphasized gregariousness, but Trotter’s book is the most elaborate and important in recent literature. Aristotle declared that man was a social animal. See Politics, Book I, Chap. I. Cf. also McDougall: Social Psychology, p. 84.