From an "In Memorial" by H. Burr Steinbach in the Biological Bulletin, Report of the General Meeting 1962, page 10.
The records show him first appearing here as a student investigator in 1912 at the age of twenty. He was elected a Member of the Corporation in 1915. The Director's report for this year records that Heilbrunn, with a few others, was responsible for raising the sum of twelve dollars to enable the library to subscribe to the British Journal of Physiology.
He was elected a Trustee in 1931 and to the Executive Committee in 1932, and over the years continued to serve the MBL in a variety of capacities. While his services to the Laboratory may lose their sharpness with the death of the man, they do not cease. At least eighteen active members of the Corporation received their doctorate degrees under his direction, as did four who have served or are serving on the Executive Committee. An equal number of workers active in the interests of the Laboratory gladly would acknowledge their direct debt to his training.
In 1917 and 1918 his name does not appear on the attendance records of the Laboratory. During these years he served as a pilot in the then new air force of his country. In a parenthetical way it could be noted that it is quite consistent with the essential daring of the man that he should be an accomplished pilot of an aircraft fifteen years before he learned to drive a car.
In 1919 the record shows him in attendance as an Independent Invesitgator from Brooklyn, New York, his home town. The record does not spell out the circumstances but one can be sure that he paused but briefly at home upon demobilization and then took off at once for his beloved Woods Hole.