"The Transmissibility of Pellagra: Experimental Attempts at Transmission to the Human Subject" is an article from [Public Health Reports (1896-1970), Volume 31](/search.php?query=collection%3Ajstor_publhealrepo1896%20AND%20volume%3A31).
...
Darwin's theory of natural selection issued a profound challenge to orthodox thought and belief: no being or species has been specifically created; all are locked into a pitiless struggle for existence, with extinction looming for those not fitted...