Mr. Youatt says, "Working cattle are most subject to locked-jaw, because they may be pricked in shoeing; and because, after a hard day's work, and covered with perspiration, they are sometimes turned out to graze during a wet or cold night. Over-driving is not an uncommon cause of locked-jaw in cattle. The drovers, from long experience, calculate the average mortality among a drove of cattle in their journey from the north to the southern markets; and at the head of the list of diseases, and with the greatest number of victims, stands 'locked-jaw,' especially if the principal drover is long absent from his charge." The treatment of locked-jaw, both in horses and cattle, has, hitherto, been notoriously unsuccessful. This is not to be wondered at when we take into consideration the destructive character of the treatment. "Take," says Mr. Youatt, "twenty-four pounds of blood from the animal; or bleed him almost to fainting.... Give him Epsom salts in pound and a half doses (!) until it operates. Purging being established, an attempt must be made to allay the irritation of the nervous system by means of sedatives; and the best drug is opium.[8] The dose should be a drachm three times a day. [One fortieth part of the quantity here recommended to be given in one day would kill a strong man who was not addicted to its use.] At the same time, the action of the bowels must be kept up by Epsom salts, or common salt, or sulphur, and the proportion of the purgative and the sedative must be so managed, that the constitution shall be under the influence of both.[9] A seton of black hellebore root may be of service. It frequently produces a great deal of swelling and inflammation.[10] ... If the disease terminates successfully, the beast will be left sadly out of condition, and he will not thrive very rapidly. He must, however, be got into fair plight, as prudence will allow, and then sold; for he will rarely stand much work afterwards, or carry any great quantity of flesh." The same happens to us poor mortals when we have been dosed _secundum artem_. We resemble walking skeletons. Our own opinion of the disease is, that it is one of nervous origin, and that the tonic spasm, always present in the muscles of voluntary motion, is only symptomatic of derangement in the great, living electro-galvanic battery, (the brain and spinal cord,) or in some of its wires (nerves) of communication. Mr. Percival says, "Tetanus consists, in a spasmodic contraction, more or less general, of the muscles of voluntary motion, and especially of those that move the lower jaw; hence the vulgar name of it, _locked-jaw_, and the technical one of _trismus_." In order to make ourselves clearly understood, and furnish the reader with proper materials for him to prosecute his inquiries with success, a few remarks on the origin of muscular motion seem to be absolutely necessary.