John Leech, Punch 33 (10 January 1857): 114
By the mid nineteenth century the ‘Great Social Evil’ was a major concern for moralists and an explosion of commentators offered suggestions on how to tackle this vice. The sin was believed to manifest itself in the form of Venereal Diseases (VD) with women as vectors and men as victims. It was a suitable punishment for committing such a sin but once VD began to pose a serious problem for the armed forces drastic measures were rolled out.
In England and Wales the Contagious Diseases Acts of 1864, 1866 and 1869 were enforced in certain port and garrison towns. The acts intended to suppress VD in the armed forces through the compulsory registration and examination of ‘prostitutes’. Glasgow was considered a good candidate for the acts but they established their own, and they argued superior, system of repression. Linda Mahood termed this the ‘Glasgow System’ which comprised of the key institutions of the Glasgow Lock Hospital, the Magdalene Institution and the Police Act 1866 which gave extensive powers including being able to enter private property and arrest ‘prostitutes’ and brothel keepers. 
However, the history is not as straightforward as it seems. Not all women who were targeted by this system of repression were sex workers and thus the word ‘prostitute’ requires historical interrogation. It is written in inverted commas for these reasons:
- it is the most appropriate word in its historical context but one which has a lot of stigma attached to it – in contemporary terms sex worker would be a better term as ‘prostitute’ is used as a slur
- the women who were profiled and targeted were often not engaging in sex work at all so we cannot accurately exchange the term for sex worker without losing its historical meaning
For the Victorians, a ‘prostitute’ was a working class women who in some way subverted middle class norms of respectability. This understanding left a considerable demographic of women (and adolescents) wide open to being institutionalised as ‘prostitutes’.
Working class sexual practises were often indistinguishable from ‘prostitution’ in the discourses of middle class philanthropists. A women need not be sexually active to be branded this way as defying middle class standards of femininity – swearing, drinking and flirting with boys – could all earn her this label from moralists. Working class adolescents were often considered a threat as they occupied the ‘public sphere’ by hanging out in the streets, the backcourts and close stairs. As adolescents these young women could instead be branded as ‘juvenile delinquents’ which for all intents and purposes made them politically ‘prostitutes’ – landing them in institutions intended to reform ‘fallen’ women or juvenile reformatories with a similar functionality. 
Glasgow Magdalene Institution for the Repression of Vice and for the Reformation of Penitent Females, c. 1890
The term was in many ways an ambiguous one yet authorities insisted on their ability to identify a ‘prostitute’ simply by looking at her. Police Constable and anti-‘social evil’ crusader, Alexander McCall insisted that:
You might as well know a prostitute as you would know a sweep; a man with a black face may not be a sweep, but at the same time you would say he was a sweep.
Any woman suspected of prostitution who could not give an adequate description of how she earned her ‘livelihood’ might be prosecuted on a police officer’s testimony alone under the Glasgow Police Acts.
McCall described his test of a ‘prostitute’:
the woman is known to be going about the streets by the police, following no other occupation, and earning her livelihood in that way
The acts enabled intensive policing of working class areas in a period when women’s employment was often seasonal, inconsistent and generally sparse so many women would have passed this ‘test’.
The ‘prostitute’ was constructed in the discourses and literature of middle class moralists; in Evangelical rhetoric, in medical literature and in law. This figure came to symbolise the moral degeneration of the industrial era and was applied to working class women in order to justify their ‘reform’. The details of this reform and how successful or not it was is far too big a question to tackle in this post.
Thoughts on historical best practice
We must interrogate the definition of ‘prostitute’ and find out who she was in practise not in discourse. If we do not then we fail to define women in their own terms and instead understand them exclusively through the eyes of the moralising patriarch. We face numerous source difficulties as the women categorised as ‘prostitutes’ rarely left diaries, memoirs or any other method of us accessing their worldview. Instead, we must read their lives through the narration of their oppressors which poses significant challenges. We must work to approach these sources with the view that these women were not merely victims of the ‘social evil’ but full historical agents.
 Linda Mahood, The Magdalenes: Prostitution in the Nineteenth Century (1990)
 I have argued this in ‘The Casualties of Industrialisation in Glasgow: Juvenile Delinquents and Magdalene Girls’ which is forthcoming and I will link to it when it is available.
Barbara Littlewood, Linda Mahood, ‘Prostitutes, Magdalenes and Wayward Girls: Dangerous Sexualities of Working Class Women in Victorian Scotland’, Gender & History 3:2 (1991)
Judith Walkowitz, Prostitution and Victorian Society Women, Class and the State (1983)