of troops. The disorganisation of them, the disarming of them. This is a French military term. To “mobilise” troops is to render them liable to be moved on service out of their quarters; to “demobilise” them is to send them home, so that they cannot be moved from their quarters against anyone. To change from a war to a peace footing.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894