Section 5. Law of Latency.—A diathesis may be transmitted through a generation without giving outward and visible sign of its existence, and may appear in full vigour in the next; or a strong neurosis may manifest itself in the intermediate generation by a temperament (group 1); and in the third break out as one of the forms comprised in third or fourth groups. The neurotic diathesis is a creeping parasite, which though a mere line on the parent trunk, yet follows each branch to its uttermost offshoots, and here and there kills a delicate twig, or envelops a whole branch, and destroys it; but sometimes, under favourable circumstances, is itself eradicated by the vigorous growth of the stock.