In 1851 the journal was acquired by John Chapman based at 142 the Strand, London, a publisher who originally had medical training. The then unknown Mary Ann Evans, later better known by her pen name of George Eliot, had brought together his authors, including Francis Newman, W. R. Greg, Harriet Martineau and the young journalist Herbert Spencer who had been working and living cheaply in the offices of The Economist opposite Chapman's house. These authors met during that summer to give their support to this flagship of freethought and reform, joined by others including John Stuart Mill, William Carpenter, Robert Chambers and George J. Holyoake. They were later joined by Thomas Huxley, an ambitious young ship's surgeon determined to become a naturalist.
Mary Ann Evans ("George Eliot") became assistant editor and produced a four page prospectus setting out their common beliefs in progress, ameliorating ills and rewards for talent, setting out a loosely defined evolutionism as "the fundamental principle" of what she and Chapman called the "Law of Progress". The group was divided over the work of Thomas Malthus, with Holyoake opposing it as the principle of the workhouse which blamed the poor for their poverty, while to Greg and Martineau this was a law of nature encouraging responsibility and self-improvement. Chapman asked Herbert Spencer to write about this divisive matter for the first issue, and Spencer's Theory of Population deduced from the General Law of Animal Fertility actually appeared in the second issue, supporting the painful Malthusian principle as both true and self-correcting.
After 1853 John Tyndall joined Huxley in running the science section of the Westminster Review and formed a group of evolutionists who helped pave the way for Charles Darwin's 1859 publication of The Origin of Species and gave it backing in the ensuing furore. The term "Darwinism" was first put in print by Huxley in his favourable review of The Origin, in the April 1860 issue of the Westminster Review.
The Nuttall Encyclopedia, published in 1907, notes that the Breeches Review was then a nickname for the journal on account of the fact that Francis Place, a breeches-maker, was a major shareholder in the enterprise.