Sentence:  The expenses are considerably reduced, and one or two men are prevented from carrying off nearly all the races ; for though " the spirit" may be ever so " willing," the " flesh is weak," and cannot stand more than five or six <WSD>gruellings</WSD> in a single day. 
Meaning of the word marked with <WSD> tags:  A race in which the animal being raced finishes in a state of physical exhaustion.