Alfred Russel Wallace - Letters and Reminiscences, Vol. 1

The publication in 1859 of the "Origin of Species" marked a distinct period in the course of Darwin's scientific labours; his previous publications had, in a measure, prepared the way for this, and those which immediately followed were branches growing out from the main line of thought and argument contained in the "Origin," an overflow of the "mass of facts" patiently gathered during the preceding years.