1. A system for detecting the presence of particular contents of a vehicular compartment, comprising: a detector system arranged to generate an output signal indicative of the absence of an object in the compartment when an object is not situated in the compartment and a different output signal indicative of a particular object in the compartment when such an object is situated in the compartment whereby different output signals are generated for different objects; and processor means coupled to said detector system for processing the output signal to create a signal characteristic of the object in the compartment which is indicative of whether the object is animate or inanimate, whereby this system is coupled to a reactive system for affecting a component in the vehicle when the created signal is indicative of an animate object.