Sentence:  "[…] They talk of you as if you were Croesus—and I expect the beggars sponge on you unconscionably." And Vickers <WSD>launched</WSD> forth into a tirade very different from his platform utterances. He spoke with extreme contempt of the dense stupidity exhibited on all occasions by the working classes. 
Meaning of the word marked with <WSD> tags:  to cause (a program) to operate