"Huxley was a man of very similar scientific type of mind (Ernst Heinrich Haeckel), but with another psychological bent to his genius. He was psychologized with the idea that there was an end-on or continuous or uniserial evolution in the developmental history of animate beings; that is, that one type led to another type — the highest of the lower order or family or group passed by degrees into the lowest of the next following or higher group. His whole lifework was based on this theory; and all his teachings — backed by much biological research and anatomical knowledge, and other factors that make a man's words carry weight — had immense vogue for these reasons."