genetic inferences, with the evil accompaniment of eager welcome for facts which agree with the favorite phylogenetic theories of the day, and of disdain for such facts as did not concord with these theories. Thus has been created that biological mythology against which Prof. E. B. Wilson has protested so suitably.
Philosophy and science are practically often incompatible—not because philosophy is unworthy of our entire respect, but because would-be philosophers are not seekers for wisdom but lovers of speculation. Twenty years ago we thought that Oken, whose Natur-philosophie was created by his speculative enthusiasm, would never have another imitator, but since then biological speculation has become almost a fetich. Let us part company from the horde of foolish thoughts which have too long masqueraded under the false garb of philosophy. For our lifetimes the labor of inductive research will suffice, and we may well leave deduction for future generations. Philosophy, so called, is often an effort to decide what must be, but while knowledge remains imperfect the "must be's" will guide us wrong more frequently than they will guide us aright. As long as Science seeks to determine what is, her work will endure. My protest against speculation is no idle rhetoric, for the evil is very great. I hope that Weismann's mystical treatise on Germplasm will prove to be the culminating effort of the speculative school, and that the influence of the school will be as brief as it has been widespread.
A hypothesis may be a good serving maid to clean away rubbish and get the workroom in order. It is for us to remember that this good maid makes the worst mistress.
There are many other difficulties of character which obstruct reason, but you will excuse me from an exhaustive review of them, and therefore I will refer only to one more, and that briefly. I mean the artistic perception which induces us to look for completeness, clearness, and simplicity, so that we are tempted to add a little or more to our conclusions, or to accept a result partly because it is complete, clear, and simple. The most eminent illustration of this tendency is Herbert Spencer, whose mental processes are so far governed by his love of clear, simple formulae that he uses simplicity as a test of his conclusions, and makes formulation a test of truth and a substitute for proof. We are all inclined to be lax as to our proofs if the generalization is satisfactory and pleasing, but Spencer's mistakes may warn us against the danger of gratifying this inclination. Science is not one of the fine arts. Its work can not be directed by the love of beauty or by sentiments. Science is a pursuit for the intellect and for the intellect alone.
I will turn to another part of our work—publication. Scientific publications naturally group themselves in four classes: origi-
