John Eglonton Seaman, Doctor of Medicine (MD), resided in Pinetown, KwaZulu-Natal, by the beginning of 1868. At that time he and Captain C.J. Harford* were instrumental in founding the Natural History Association of Natal. At the association's first general meeting on 3 February 1868 Seaman was elected its honorary corresponding secretary and at an inaugural conversazione on 13 March he (among others) spoke on the objects of the association and exhibited a collection of butterflies. One of the ideals of members was to establish a museum. However, in a letter to the Natal Mercury of 18 January 1868, signed "J.E.S." (most probably J.E. Seaman) the writer warned that the association should not be too hasty in soliciting specimens, as the proper care of a museum collection would require the appointment of a full-time paid curator. The association did not establish a museum during its short life.
Seaman delivered two papers at meetings of the association. The first, "Instances of variation by natural selection of Rhopalocerous Lepidoptera in Natal", delivered on 29 September 1868, probably formed the basis of an article published under his name in the Cape Monthly Magazine (August 1871, Vol. 3, pp. 77-80) entitled "Variation in butterflies". The second, "Protective resemblances in some local forms of insect life", was delivered on 23 August 1869. He chaired a meeting of the association on 5 January 1871 and was present at its last recorded meeting on 20 April that year. Long after his death Roland Trimen* of the South African Museum, Cape Town, in the preface to his book South African butterflies... (1887-1889), acknowledged Seaman for presenting him with a small series of Natal butterflies, with drawings of larvae and pupae.
Seaman was one of the foundation members of the Durban Medico-Chirurgical Society, established in 1871 or 1872. However, he was not included in a list of medical men licensed to practice in Natal publised in the Natal almanac for 1872. Furthermore, from 1870 to 1873 his address (as corresponding secretary of the Natural History Association) was given as London in the Natal almanac, which probably means that he spent only part of his time in Natal between 1870 and his death in 1873. He was survived by his wife, Marie Charlotte Seaman.