It is now generally recognized that certain crimes are committed under the influence of impulses so strong as to be practically irresistible. The circumstances in which impulses become so strong have been much discussed. It is recognized that if a man has done irrational deeds early in life, that is, if he has performed serious acts entirely disproportionate to the motive urging him to their accomplishment, he is lacking somewhat in responsibility. If to this be added the fact that there is a nervous heredity, that is, that certain members of the family in previous generations have behaved irrationally, especially in crises of conduct; then, in the opinion of many authorities, responsibility seems to be seriously impaired. These are practically the doctrines that the medical profession, in the progress of its growing knowledge of mental diseases, has labored, with no inconsiderable success, to graft on our criminal code, until now