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Rh subject, notwithstanding that it can not be manifested at birth, as in the case of quadrupeds.

2. When I composed "The Senses and the Intellect," the doctrine of evolution was not before the world in any shape. I made no attempt to frame an hypothesis to account for our instincts; I assumed them as I found them, and described the progress of the individual acquisitions as they appeared to my observation. In my subsequent writings I have made ample use of the hypothesis, so far as I think it agrees with the facts. I may refer more particularly to the third edition of "The Emotions and the Will," published not long ago. In "Mental and Moral Science" I allow for the probability of hereditary acquisitions in reference to the various relations summed up in the knowledge of space.

3. My theory of the will, as first conceived, was the expression of the facts as I was able to view them at the time. I regarded as acquisitions everything that appeared to need teaching in some shape or other; as, for example, speech. I inquired what were the powers that existed in the absence of teaching, and what were those that came into being only by teaching, or by some sort of experience or acquirement. I may have misconceived the scope of the two departments; but, to the best of my knowledge at the time, I endeavored to appreciate the extent of each. I saw that an infant at the end of a few months could perform simple articulations, as wa, na, bo, bu, and that on these could be based the instruction in speech. I did not consider that the articulations could be taught; I was inclined to believe that they might be stumbled on by random tentatives. I now proceed to remark on Professor Spence's reductio ad absurdum of that operation.

4. When the Professor talks of the number of muscles that must come into play in pronouncing the letter A, and of the enormous unlikelihood of a child stumbling on the right one in a few months, he leaves out of account various circumstances. For one thing, the combinations are absolutely limited by mutual conflict; only such groupings as can go together are to be allowed. How far this would reduce the possible number of trials I do not say, nor do I mean to affirm that the number would not remain very large; still his figure would be very seriously reduced. I will take a more patent example than speech, namely, the movement of the eyes. We know that six muscles are at work; and, allowing several gradations of energy to each, say four, there are twenty-four elements to play upon in every variety of combination. But now, instead of summing the arithmetical possibilities of union among these elements, let us survey the outcome. Of course in many of the combinations, as when two opposing muscles were equally stimulated, there would be no result; there would be simply a shock of painful collision. When the stimuli are unequal, there would be motion in some one course&mdash;up, down, right, left, slanting, curved. The possibilities now are not so very formidable: the eye can only