His academic colleagues remained in that isolation which he had ever bitterly resented. In face of this situation, which seemed to grow more sombre as the last years of the century dragged on, his zeal for truth and progress had but one outlet. He must appeal to the people. He must take the conclusions he had so laboriously worked out in his _Systematic Phylogeny_, and translate them from scientific hieroglyphics into a demotic tongue. He must nail his theses with his own hand on the cathedral door, like the great monk whose work seemed in danger of perishing. The partial success of his _History of Creation_ was encouraging, though that work had only penetrated into the first circle beyond the sacred academic enclosure, and was still unknown to the crowd. Gathering his strength for what he believed to be his final effort, he blew a blast that would reach the far-off shop and factory. It must be no gentle note, no timid suggestion that the scientific work of the nineteenth century had thrown doubt on current religious notions. He was quitting the stage. He believed these things were true, were established. The world must listen to them, must discuss them; and then the twentieth century would pass its informed verdict over his grave. So he wrote a vigorous, an irritating, an awakening book. It must be read in this context. The charge of “dogmatism” so often hurled at it is not without humour. It is generally raised by men who in the same breath hold their truths so dogmatically that they resent his very questions. They forget, too, that the chief conclusions of the _Riddle_ are references to the larger work in which, soundly or unsoundly, they are provided with massive foundations of scientific material. In England there is some excuse, as the larger work is untranslated and unknown; though one may resent the critic who charges Haeckel with egoism for his constant references to his other works and then proceeds to ridicule the slenderness of the foundations of his theories. Further, it is too often forgotten that Haeckel opens his work with a rare warning to the reader that his opinions are very largely “subjective” and his command of other subjects than biology is very “unequal.” In fine, his constant and exaggerated allusions to the opposition he encounters from his scientific colleagues is, for any candid reader, a sufficient corrective of “dogmatism.”