Dutch naturalist and museologist whose surname is given as both Breijer and Breyer. After receiving his doctorate from the University of Amsterdam, he moved to South Africa to take up a teaching position. In Pretoria he became a trustee of the newly founded Staatsmuseum (renamed the Transvaal Museum and Zoological Gardens in 1901), and served as curator until 1897. In 1913, after many years lecturing in natural science and mathematics, he was made director of the Transvaal Museum, and until his retirement in 1921 collected locally and on expeditions with original material deposited at the museum (TRV). Collections at TRV were later transferred to PRE. Cleome breyeri Burtt Davy, Disa breyeri Schltr. and Warburgia breyeri R. Pott are among the species named in his honour.