Recent scholarship on the social history of health and medicine in colonial India has moved beyond enclavist or hegemonic aspects of imperial medicine and has rather focused on the role of Indian intermediaries and the fractured nature of colonial hegemony. Drawing inspiration from this scholarship, the article highlights the significance of the Indian subordinates in the lock hospital system in the nineteenth century Madras Presidency. This study focuses on a class of Indian subordinates called the "gomastah", who were employed to detect clandestine prostitution in Madras to control the spread of venereal disease. It also underlines the role of other native and non-native subordinates such as Dhais, Chowdranies and Matrons, the ways in which they became indispensable for the smoother operation of the Contagious Diseases Act and the lock hospitals on a day-to-day basis. By emphasising how Indian subordinates were able to bring in caste biases within colonial governmentality, adding another layer to the colonial prejudices and xenophobia against the native population, it underlines the fact that there was not a one-way appropriation or facilitation of the coloniser's knowledge or biases by the colonised intermediaries. Rather, it argues for an interaction between them, and highlights the complexities of caste hierarchies and prejudice within the everyday colonial governmentality. Moreover, the article focuses on the consequent chaos and inherent power struggle between different factions of colonial staff.