If this be the correct explanation, we should expect that when a white woman married first a black man, and then a white, the children by the white husband would be dark colored.

Unfortunately for the proof of telegony, it is very rare that a white woman does marry a black man, and then have a white as second husband; nevertheless, we have a fair number of recorded instances of dark-colored children being born in the above way of white parents.
"Dr.Harvey mentions a case in which 'a young woman, residing in Edinburgh, and born of white (Scottish) parents, but whose mother, some time previous to her marriage, had a natural (mulatto) child by a negro man-servant in Edinburgh, exhibits distinct traces of the negro.

Dr.
Simpson--afterward Sir James Simpson--whose patient the young woman at one time was, has had no recent opportunities of satisfying himself as to the precise extent to which the negro character prevails in her features; but he recollects being struck with the resemblance, and noticed particularly that the hair had the qualities characteristic of the negro.' Herbert Spencer got a letter from a 'distinguished correspondent' in the United States, who said that children by white parents had been 'repeatedly' observed to show traces of black blood when the women had had previous connection with (i.e., a child by) a negro.

Dr.Youmans of New York interviewed several medical professors, who said the above was 'generally accepted as a fact.' Prof.Austin Flint, in 'A Text-book of Human Physiology,' mentioned this fact, and when asked about it said: 'He had never heard the statement questioned.' "But it is not only in relation to color that we find telegony to have been noticed in the human subject.

Dr.Middleton Michel gives a most interesting case in the American Journal of the Medical Sciences for 1868: 'A black woman, mother of several negro children, none of whom were deformed in any particular, had illicit intercourse with a white man, by whom she became pregnant.