ACTION AND USES OF TAR, ETC. 485 



A lotion of oil of tar, sulphurated potassa, or Peruvian 

 balsam, is more cleanly and suitable for house dogs with 

 eczema. (See diet for eczema in dogs, section on foods and 

 feeding, p. 657.) Tar is of the greatest utility in stimulating 

 the growth of horn, and is the' principal ingredient of hoof 

 ointments for horses. It may be mixed with an equal 

 part of lard for this purpose, or the following mixture is well 

 spoken of : tar, yellow wax and honey, ^ lb. each ; lard, 1 J 

 lbs.; glycerin, 3 ounces. Melt and mix the lard and wax 

 together ; add the other ingredients ; stir while cooling. 

 Oakum, soaked with tar, is frequently packed under leather, 

 beneath the shoes on horses' feet, to soften and stimulate the 

 horn and to cure thrush and canker. Tar is also a beneficial 

 application for foot rot of sheep. Tar is usually kept on 

 hand for farming purposes, and is therefore a. popular anti- 

 septic and protective in the treatment of wounds and broken 

 horns in cattle. 



Internally. — Tar — on account of its constituents, phenol 

 and creosote — in large quantities causes toxic effects, with 

 symptoms resembling carbolic acid poisoning: e.g., abdominal 

 pain, vertigo, signs of gastro-intestinal irritation, and the 

 passage of dark-colored urine. It is not exceedingly pois- 

 onous, however, as recovery has been reported in man after 

 the ingestion of an amount varying from one to two pints. 

 Tar is eliminated by the kidneys, with the production of 

 irritation and diuresis ; also by the mucous membrane, and 

 affects more especially that lining the bronchial tubes, where 

 it acts as a local stimulant and antiseptic. For this reason 

 the drug is an excellent expectorant in subacute or chronic 

 I bronchitis when given internally or by inhalation. The latter 

 ^process may be conducted by pouring tar on a heated shovel, 

 or, better, by dissolving tar in boiliug sodium carbonate 

 solution and steaming the patient with the vapor. Tar is 

 occasionally exhibited in chronic gastro-intestinal catarrh 

 and obstinate diarrhoea, with good results. 



Tar is of value internally in influencing those skin 

 disorders which are benefited by its external application. 



