This section is from the book "The Dogs Of Great Britain, America, And Other Countries. Their Breeding, Training, and Management in Health and Disease", by John Henry Walsh (Stonehenge). Also available from Amazon: The Dogs Of Great Britain, America And Other Countries.
Resembling rabies in some degree, tetanus differs from it in the absence of any affection of the brain, the senses remaining perfect to the last. It is not common with the dog. It is generally produced by a severe injury, and shows itself in the form known as "lock-jaw." It consists in spasmodic rigidity of certain muscles, alternating with relaxation. The stiffness continues for some length of time, not appearing and disappearing as quickly as in cramp
If the tetanic spasm affects the muscles of the jaw, the state is called "lock-jaw." When it seizes on all muscles of the back, the body is drawn into a bow, the head being brought in close proximity to the tail. Sometimes the contraction is of one side only and at others of the muscles of the belly, producing a bow in the opposite direction to that alluded to above. These various conditions exactly resemble the contractions produced by the poison of strychnine. When, therefore, they occur, as the disease is extremely rare, it is fair to suspect that poison has been used. Nevertheless, it should be known that they were witnessed long before this poison was in use; and, therefore, they may arise independently of it. The successful treatment of tetanus is hopeless, if the case is clearly established. Purgatives and bleeding may be tried, fol-lowed by chloroform, which will always relieve the spasm for the tide; but, as it returns soon after the withdrawal of the remedy, no permanent good is likely to accrue from its use.
Except in the case of highly valued dogs, I should never advise any remedies being tried; the humane course is to at once put the poor animal out of misery, the spasms being evidently of the most painful nature.