This is an account of Professor Jelgersma's psycho-analytical contributions and influence, referring to the public announcement of his support in 1911 and his share in founding the Nederlandsche Vereinegung voor Psychoanalyse in 1917.

While not opposed to theoretical speculations he accords priority to empirical observation. He has not himself, however, eschewed theorizing. Much of his earlier pre-analytical work was in harmony with the Freudian standpoint. He has advocated the separation of neurology and psychiatry.