The balking horse is one that obstinately refuses to perform a piece of work for which his physical condition seems to be well adapted. The _willfulness_ of the refusal is the important feature. In case of such a serious drawback to the value of a horse, the presumption of fraud on the part of the seller is unavoidable, in case he failed to mention the habit to the purchaser, but of course this is even more emphatically certified if he has warranted the animal as a _good worker_, or _kind_, or _true in work_. On the other hand he cannot be held responsible for the failure to perform an act in case the horse has been overloaded when fat or out of condition, or if he has sores on back, withers or shoulders, a badly fitting collar, a severe or large clumsy bit, or sores on the lower jaw, or indeed any temporary physical infirmity, to which the balking can be fairly attributed. Balking is not to be confounded with nervous affections (paretic, spasmodic, congestion) in which the failure to obey is not due to lack of will, but to lack of power. Nor must it be confounded with the inability of the paralysis of lead poisoning. It is perhaps most likely to be confounded with that lack of both sensory and motor power which attends on ventricular dropsy and other chronic affections of the brain. In such cases (immobility, coma) the habitual dullness, drowsiness, general hebetude, and lack of energy contrasts strongly, with the strength, vigor and general life of the animal which suddenly, willfully and incorrigibly balks. The balky horse which has no such nervous disorder as an excuse, no badly fitting harness, no lesion on shoulder, back, limbs nor mouth, no unsuitable bit, no special softness nor poverty of condition, no slow, ill-adjusted mate, no impatient driver, and no excessive load, nor impassable road, but which jibs without excuse, as a willful disobedience, may well be cause for annulling a sale. In most European countries such a horse can be returned to the seller and the sale set aside within 3 days (Austria), 4 days (Prussia), 5 days (Saxony), 9 days (Hesse). _Treatment_. This should be preventive by avoiding the various causes above enumerated, for if the habit is once contracted it is too often impossible to establish a permanent cure. The horse is largely a bundle of habits and the first act of disobedience has given a bias to the nerve cells of the cortex cerebri which like a planted seed tends to reproduce itself whenever an opportunity offers. With every successive act of the kind, the impression on the nerve cells becomes deeper and more indelible and the habit fixed the more firmly.