Our bloody nature, it can now be argued in the context of modern biology, is ingrained because group-versus-group was a principal driving force that made us what we are. In prehistory, group selection lifted hominids to heights of solidarity, to genius, to enterprise. And to fear.
— E. O. Wilson, Harvard biologist
Label on verso read: The blood in myeloid leukaemia stained with Ehrlich’s triple stain. After Gulland and Goodall, The Blood: A Guide to its Examination, Edinburgh, 1912 ; The first satisfactory method of obtaining differential staining of the blood cells was due to Ehrlich, who made use of the newly discovered analine dyes … but its historical importance is great