Marcus Manuel Hartog (19 August 1851, London – 21 January 1924, Paris) was an English educator, natural historian, philosopher of biology and zoologist in Cork, Ireland.
His two younger sisters were the pianist and composer Cécile Hartog and the portrait painter Héléna Arsène Darmesteter, Marcus Hartog was educated at the North London Collegiate School, University College, London, and Trinity College, Cambridge, where he took a first class in the National Science Tripos in 1874, and went out in the same year to Ceylon as assistant to the Director of the Royal Botanic Gardens — a post that he held for three years.
On his return he became a demonstrator, and afterwards a lecturer in natural history at Owens College, Manchester.
In 1882 he began an association of more than 40 years with the educational life of Cork.
[2][3][4] He argued that cell division occurs due to a new force he termed "mitokinetism".