Lastly, in 1898, appeared the first volume of what may be called his crowning work, 'Vergleichende Anatomie der Wirbelthiere.'
Gegenbaur is universally recognised, not only as the greatest living comparative anatomist, but also as the founder of the modern side of this science, by having based it on the theory of descent.
In 1896 he received from the Royal Society the Copley medal 'for his pre-eminence in the science of comparative anatomy or animal morphology.'
His marvellously powerful influence as a teacher and investigator has made Heidelberg a centre whence many pupils have spread his teaching, and above all his method of research.
Ernst Heinrich Haeckel was born on February 16, 1834, at Potsdam. He carried out his academical studies alternately at Berlin and Würzburg, attracted by such men as Johannes Mueller, Koelliker, and Virchow. For years he was undecided what his career should be, whether that of botanist, collector, or geographical traveller. Certainly that of medicine attracted him least, although in deference to his father's wishes he qualified and settled down for a year's practice in Berlin. As he himself has told us, he might perhaps have proved rather successful as a physician, to judge from the fact that he did not lose a single patient. But 'I had only three patients all told, and the reason of this is perhaps that I had given on my plate the hours of consultation as from 5 to 6 a.m.'
During the year 1859 he travelled as medical man and artist in Sicily. In 1861 he was induced by Gegenbaur, whose acquaintance he had made in Würzburg, to establish himself as a Privat-docent for comparative anatomy in Jena. And there he has remained ever since, filling the Chair of Zoology, and having declined several much more tempting offers from the Universities of Würzburg, Vienna, Strassburg, and Bonn.
Within one year, 1865, he wrote the two volumes of his 'Generelle Morphologie der Organismen,' as he himself relates, in order to master his sorrow over the loss of his first wife. But he broke down, and went to the Canaries to recruit health and strength. The 'Morphologie,' which has long been out of print,[26] made scarcely any impression. It was ignored, probably because he had placed the old-fashioned study of zoology and morphology upon a thoroughly Darwinistic basis.
On the advice of his friend Gegenbaur, he gave a more popularly written abstract of his 'Generelle Morphologie'—in fact, the substance of a series of his lectures—in the shape of his 'Natürliche Schöpfungsgeschichte.' This 'History of Natural Creation,' which in 1898 has reached the ninth edition (first edition translated into English in 1873), had the desired effect. So also had his '[Anthropogenie] oder [Entwicklungsgeschichte] des [Menschen],' the fourth edition of which appeared in 1891.
It was a lucky coincidence that Haeckel had just finished his preliminary academical studies, was entirely at leisure, and undetermined to which branch of natural science he should devote his genius, when Darwin's great work was given to the world. Haeckel embraced the new doctrine fervently, and, as Huxley was doing in England, he spread it and fought for it with ever-increasing vigour in Germany.