The image is taken from the psychiatry section of the Science and Society picture library and depicts a male anti-masturbation device from the late 19th / early 20th century, and, believe it or not, was considered an effective way of preventing insanity.
Masturbation was long linked to madness in both folk and professional medicine and this belief lasted, even among professionals, until the early 1900s.
It was thought a particular mental health risk in children, as illustrated by this excerpt from a 1988 article on the development of child psychiatry in 19th century Britain.
William Acton, trained in surgery and venereal diseases, published The functions and disorders of the reproductive organs, in youth, in adult age and in advanced life in 1857. It gained immediate popularity and went through six editions in 18 years, despite it’s many discrepancies, premature conclusions and emotional prejudices (Marcus, 1966).
Typical of most authors of the time, Acton on the one hand postulates that normal childhood is essentially asexual, on the other describes over many pages the many sexual disorders of childhood ‚Äî a conflict that is never resolved. Again, without further explanation, a causal connection between masturbation and a whole array of consequences is drawn: the boy would become haggard, thin, antisocial, hypochondriacal, would lose his spontaneity and cheerfulness and would turn into a timid coward and liar. The final state was one of idiocy, epilepsy, paralysis and even death.
These prejudices were considered valid scientific facts, so that the Scottish psychiatrist David Skae even created the term “masturbatory insanity” ‚Äî a separate nosological disease caused exclusively by masturbation, with characteristic features (Skae, 1874). This term was taken up by Henry Maudsley (1868); the 1879 edition of Pathology of mind included a chapter devoted to the insanity of masturbation (Maudsley, 1879), which was later changed to insanity and masturbation (Maudsley, 1895).
I’ll save you the gory details, but these beliefs led to supposed ‘treatments’ and ‘preventative measures’ that stretched from devices like the one pictured, to what would now be considered brutal genital mutilation of both boys and girls.
If you think that these were fringe beliefs, it’s worth remembering that Henry Maudsley was otherwise considered the greatest psychiatrist of his generation.
Link to picture from Science and Society image library.