So that the theory of the born criminal must be relegated to the limbo of discarded theories, and it is futile to attempt to identify a criminal type solely by means of anatomical and physio logical traits. The study of these external, physical traits is of significance only when correlated with the internal traits, namely, the mental traits.
The physical basis of mind is neural. All of the mental phenomena, namely, the instinctive, the affective and the intellectual phenomena, take place through the agency of the nervous system. The instincts function, in the first place, because stimuli from sense organs pass over nerve fibres to the central nerve cells which constitute the centres for the instincts in the central nervous system. These centres are probably located mainly in the spinal cord, the medulla and the cerebellum. The instincts func tion in the second place, because impulses are sent out from these centres and travel over nerve fibres to the muscles which perform the instinc tive acts. Feelings are possible only where nerve fibres are present, and probably arise mainly as a result of stimulation of the sympathetic nervous system. The intelligence is localized in the association areas of the cortex of the brain. Consequently, inherited variations in the ner vous system may give rise to exceptional strength or exceptional weakness of some of the instincts and feelings. In similar fashion, use or disuse may lead to acquired variations which may in turn result in the accentuation or inhibition of instincts and feelings. It is doubt less true that some persons are born with traits which make them peculiarly disposed to com mit crimes if their environment is conducive to criminal conduct, and a portion of the crim inal class is recruited from this group. Thus abnormal variations may take place in sensory, motor or central nerve centres which make cer tain instincts stronger or weaker. Or varia tions may take place in sensory or central nerve centres, or in some of the viscera, which change the feelings in such.a fashion as to lead to criminal conduct. Or variations may take place in the cortex of the brain which weakens the intelligence. Some of these variations are hereditary. But many of the anatomical and physiological traits which are abnormal from the time of birth are more likely to be due to irregularities in the development previous to birth, such as are due to pressure on the brain, ill-nutrition, etc. Sometimes these abnormali
ties do not appear until later in life, but are due to congenital weaknesses which constitute a diathesis or predisposition for acquiring these abnormalities. These abnormal and pathological traits result in abnormal conduct of all kinds. The excessive strength or weakness of some of the instincts furnishes a powerful impulse toward crime, or removes a powerful restraint which acts upon most persons. In similar fashion, the excessive strength or weakness of some of the feelings furnishes a powerful impulse toward some kinds of criminal con duct, such as crimes of passion, or removes the restraint from certain other kinds of criminal conduct. The weakness of the intelligence makes it difficult or impossible for the ament or feeble-minded person to understand the nature of or the justification for the regulations and restrictions imposed upon him by society. Owing to these abnormalities, the individual does not succeed in adjusting or adapting him self to•social life, or, at any rate, to the life of the society to which he belongs. Recent investi gations indicate that in all probability a mini mum of 5 per cent of criminals are aments, and that there are probably at least 10 times as many aments proportionally among the crim inals as there are in the population at large. It is even more difficult to estimate the number of psychopathic criminals. Among these are the demented, the insane and the neurotic crim inals. Dementia precox characterizes some of the younger criminals. Manic-depressive insan ity and paranoia are more or less prevalent among the insane criminals. Epilepsy char acterizes some criminals. Hysteria, neuras thenia and psychasthenia are other neuroses which are found among criminals probably much less frequently than epilepsy. Bad habits, such as alcoholism and drug habits, excessive suggestibility, mental conflicts and repressions, etc., are other abnormal traits which give rise to criminality or at least aggravate it.