Preparation of the Injection Fluids.—­Have on hand a pint of a one per cent aqueous solution of formaldehyd made under cleanly conditions, even to a clean bottle and cork, and a clean container when ready to use the liquid.  Prepare also a bichlorid of mercury solution as follows:  Hydrarg.  Chlor.  Corros. 3IV; Acid Hydrochlor. 3Iss.; Aqua Bulliens, Oij.  This should be thoroughly triturated, and then filtered into a clean bottle, when it is ready for use.

Injection.—­The patient should be laid on a table, if one is available, or cast, and the foot securely fixed.  Then, with an ordinary one-ounce hard rubber syringe, with a good plunger (tried first to note whether or not any fluid works around between the barrel and the plunger), introduce one syringe full of the formaldehyd solution, then thoroughly probe the quittor to determine the number of sinuses.  This done, inject each sinus.  If two sinuses open on the surface, close one with cotton while filling the other so that if there is a connection the solution will come in contact with all tissues involved.  Irrigate with the full pint of formaldehyd solution first, then follow with six or eight ounces of the bichlorid solution.  Never probe the foot nor allow it to be tampered with except in the manner prescribed.

After-Treatment.—­Put on a pack saturated with a solution of bichlorid of mercury 1 to 1,000 and let it remain two days.  Remove pack, and once daily afterwards wipe off with cotton the secretion which accumulates on the outside, and apply a dry dressing or healing oil composed of phenol, camphor gum and olive oil.

When Dangerous to Inject.—­Never inject a quittor in the acute stage.  Never inject a quittor if considerable lameness is present.  On injecting a solution of formalin, hold cotton tightly around the nozzle of the syringe, when the plunger is down, then withdraw the syringe gently and note particularly if the fluid returns through the opening; if none returns cease operations at once, as it is dangerous to proceed farther, it indicates that the sinus is not well defined and the fluid retained will cause much trouble and often the death of the patient.

Experience has taught that, if extensive destructive changes of the foot exist, the Bayer operation is not indicated.  In the country, where quittors are not so frequently met as in urban practice, the Merillat operation is preferable in all cases.  However, the cost of the protracted period of idleness, which convalescent surgical patients require, renders the Hughes method more satisfactory in the hands of the general practitioner, especially in the city.

Nail Punctures.

Nail punctures, as herein considered, embrace all penetrant wounds of the solar surface of the horse’s foot due to trampling upon street nails.  This does not include accidental nail pricks occasioned in shoeing.  In city practice, in some stables, these cases are of frequent occurrence; and, generally speaking, nail punctures are observed more frequently in urban horses than in animals that are kept in the country.