About the time his housekeeping experience was entered upon, Mr. Spencer found himself well enough to go on with the composition of his Philosophy. As he relates in the preface to the Data of Ethics and to Justice, he had already, ten years before, in the imminent doubt of ever being able to complete the work as it had been laid out, determined to devote his attention first to the end and ultimate object of the system--to that part of it to which all the rest was intended to lead up; the purpose, "lying behind all proximate purposes," of finding a scientific basis for the principles of right and wrong in conduct at large. When, now, the question arose again of what work to undertake first, completion of the Principles of Ethics was at once decided upon. As it was still doubtful whether he would be able to accomplish even this, he took up the part which seemed most important--Justice. This was published as Part IV of the Ethics in the summer of 1891. No further serious interruptions occurred in the execution of the work. Parts II and III, completing the first volume of the Ethics, were finished in the spring of 1892; and a year afterward Parts V and VI were added, forming, with Justice, the second volume. The ethical part of the Philosophy as contemplated by Mr. Spencer having been completed, only two divisions remained to be worked out--Professional Institutions and Industrial Institutions, parts of the Principles of Sociology--to fill out the whole plan. A subsidiary discussion of considerable importance for the integrity of the theory of evolution now intervened to be disposed of before these parts of the work could be proceeded with. Prof. August Weismann had published a book in which he denied the transmission of acquired characters; or, as Mr. Spencer would word it, the transmission of functionally-wrought modifications--a very vital point in all Mr. Spencer's philosophy. Mr. Spencer took the matter up at once, and published several incisive essays refuting Professor Weismann's positions. He opened his argument against the neo-Darwinian position with essays on the Inadequacy of Natural Selection, and on Professor Weismann's Theories, and followed them, at intervals of a few months, with the additional articles, A Rejoinder to Professor Weismann, and Weismannism Once More. Anxious that the question should be brought to the notice of every biologist, Mr. Spencer had reprints of these essays distributed among the teachers of the science all over Europe and America.