a _conclusion_; which latter practice is like that of people asking advice, and only following it when it chimes in with their desires. 114. Is not the warning needed, when we find anatomists guided by certain “physiological postulates,” and consequently _seeing_ only what these postulates demand? For example, there is the postulate of “isolated conduction,” which is said to require that every nerve-fibre should pursue its course singly from centre to periphery. Accordingly the fibres are described as unbranched. Whatever may be the demand of the postulate, or the felt necessity of the deduction, the fact is that nerve-fibres do branch off during their course at various points; nay, it is doubtful whether any lengthy fibre is unbranched. Other postulates demand what fact plainly denies. It is said to be “necessary” that every cell should have at least two fibres, and that sensory and motor nerves should be directly connected through their respective cells. These things cannot be seen, but they are described with unhesitating precision. Diagrams are published in which the sensory fibres pass into the cells of the posterior horn of the spinal cord, and these cells send off prolongations to the cells of the anterior horn, and thence the motor fibres pass out to the muscles: an absolutely impossible arrangement, according to our present data! Again, the postulate that nerve-force originates in the cells, and that nerve-functions depend on cells, required that the cells should be most abundant where the function was most energetic. Of course they were found most abundant in the required places--no notice whatever being taken of the facts which directly contradicted the deduction. 115. Among the serious obstacles to research we must reckon this tendency to substitute Imaginary Anatomy for Objective Anatomy. I am conscious of the tendency in myself, as I note it in others; and have constantly to struggle against it, though not perhaps always aware of it. Many a time have I had to relinquish plausible explanations, which would have supported my speculations could I but have believed that they represented the facts; but being unable to believe this, I had to remember that hypotheses and explanations appear and disappear--only the solid fact lives. If there is one lesson emphatically taught by Philosophy, it is the unwisdom of founding our conclusions on our desires rather than on the objective facts.