From this passage it will be seen that ascertained facts are given in harmony with previous descriptions; but that while naming some as sensory, others as motor, there is no distinct evidence for classifying certain cells as "mind-cells." Along with the admission of our comparative ignorance of the minute structure of the cell, is the assertion that this cell "possesses the capacity to feel, to will, to think." This latter statement is advanced without any trace of scientific evidence, and has no better substratum on which to rest than the admission that man not only feels, but also thinks and wills. Further, when we recall the singular variety of situation in which these cells are found, as they lie within the spinal canal, subordinate centres, and the brain, the insufficiency of the whole theory of "mind-cells" is apparent. Still more conspicuous does this become when we turn to Hæckel's illustrative diagram, and read underneath it this description,--"A large branched nerve-cell, or 'mind-cell' from the brain of an electric fish." The investigator who makes in the directest manner statements as to thinking and willing, which he has not verified and can not verify; and who with undisturbed composure of mind proceeds to illustrate and support his position by giving a drawing of the "mind-cell of an electric fish," does almost every thing that can be done to discredit his testimony on scientific subjects. Having now set forth the grounds on which I think it clearly shown that physiological science has done no more than identify sensory and motor cells; and that the search for the true "mind-cell" has proved a failure; I pass from this division of the subject with the acknowledgment that the front and back portions of the brain still present area for fresh research, and to this must be added the striking fact that in all the brains subjected to electric excitation these two portions have uniformly remained silent. These considerations may possibly hereafter afford valuable suggestions towards guidance of the work yet to be done in the investigation of brain structure and functions.