Sentence:  Now that the detectives were in adversity, the newspapers turned upon them, and began to fling the most stinging sarcasms at them. This gave the minstrels an idea, and they dressed themselves as detectives and hunted the elephant on the stage in the most extravagant way. The caricaturists made pictures of detectives scanning the country with spy-glasses, while the elephant, at their backs, stole apples out of their pockets. And they made all sorts of ridiculous pictures of the detective badge—you have seen that badge printed in gold on the back of detective novels no doubt, it is a wide-staring eye, with the legend, “WE NEVER SLEEP.” When detectives called for a drink, the would-be facetious barkeeper resurrected an obsolete form of expression and said, “Will you have an eye-opener?” All the air was thick with sarcasms. But there was one man who moved calm, untouched, unaffected, through it all. It was that heart of oak, the chief inspector. His brave eye never drooped, his serene confidence never wavered. He always said: “Let them <WSD>rail</WSD> on; he laughs best who laughs last.” 
Meaning of the word marked with <WSD> tags:  To complain violently ((against), (about)).