M. Horace Hayes, Illustrated Horse Breaking
“ A jibber in draught, however, is apt to find out, that although the breaker is all-powerful, when it has no harness on; the advantage is all the other way, as soon as it{19} gets between the shafts; it being easier, as Professor Sample used to say, to break a horse than to break a horse and trap. Besides this, it is impossible, in many cases, to directly apply breaking methods to animals in harness, in the same manner as we can do in saddle. ”
