The scientific controversy over the gastræa-theory was in full swing when Haeckel entered upon another bold experiment in the direction of the biogenetic law. He thought it would be useful, instead of framing wider hypotheses, to take one single instance of one of the highest animals, and trace the whole parallel of its embryonic and ancestral development down to its finest details. It would serve as an excellent object-lesson. He would take it, not from some remote corner of the system, such as the sponges or medusæ, but from the very top of the tree, where palingenesis and cenogenesis seemed to have culminated in an inextricable confusion. But what example could be more appropriate and effective than the most advanced of all living things—man. He would write a monograph on man on an entirely new method; would show ontogeny and phylogeny confirming each other down to the smallest detail. It was another great enterprise. And this particular subject was so interesting that it would appeal strongly to the general readers of his _History of Creation_ as well as to the academic scientists. Man was a subject of such obviousness and importance to the layman that in this case there was really no professional limitation of interest at all. Every detail in the most technical treatment of the subject would be taken into account, and evoked his strongest sympathy. When Haeckel had fully matured this plan, he produced his _Anthropogeny_.[6] The word, founded on the Greek, means the “genesis” or “evolution of man.” Footnote 6: The fifth edition is translated into English, with all the plates and illustrations, under the title of _The Evolution of Man_. [Trans.]