The work on the final stage of Mr. Spencer's great undertaking was begun about the middle of 1894. The reading of an editorial in the Popular Science Monthly having suggested to him that it would be desirable to do so, he published the chapters on Professional Institutions--serially in this periodical and in the Contemporary Review. The chapters on Industrial Institutions did not appear till the third volume of the Sociology was issued in November, 1896--the volume which was the culmination of the work so persistently prosecuted in the face of the most formidable and even seemingly hopeless difficulties. In these departments of the system, the argument was pursued, consistent with that which prevails in all the other departments, that in the professions and the industries the principle of evolution operates just as surely and completely as in the derivation of an animal species from its ancestral form. Appreciation of the value of Mr. Spencer's work had been growing for many years, and its influence was gradually making itself felt in movements of various kinds in the active world. Whatever he wrote or said received attention at once, was discussed, or influenced action. The completion of his Philosophy was deemed worthy of formal notice and a proper subject for felicitation wherever science was known, and in England was regarded as a suitable object for a national memorial. An address of congratulation was prepared for presentation to him, and with it went a request that he would have his portrait painted to be presented to the nation. It has always been his principle to decline offers of testimonials, on the ground that the custom had become an abuse, and persons invited to participate in presentations were often put under a kind of moral obligation to comply, to which he would not be, even incidentally, a party. Consistently with this attitude and not realizing the real nature of the movement in favor of a testimonial and how really spontaneous it was, he wrote to its promoters repeating his objections and asking that it be not pressed. But when the address was presented and he saw the list of illustrious names attached to it, including those of men who had been his antagonists, he yielded to what was evidently a spontaneous feeling of the representative men among his countrymen, and sat for his portrait as soon as circumstances permitted, or about a year afterward, to Mr. Hubert Herkomer. The following is the letter of congratulation and the request for his portrait, with the names of the distinguished signers, and Mr. Spencer's reply: THE CAMP, SUNNINGDALE, _December 16, 1896_. DEAR SIR: We, the undersigned, offer you our cordial congratulations upon the completion of your System of Synthetic Philosophy.