DISEASES. 605 



Verrier, Jr., of Rouen; a solution of sulphate of copper and of 

 zinc in water or vinegar were recommended by Delaval and Haub- 

 ner ; Solleysel emj)loyed the j)reparations of copper, but added to 

 them arsenic and other di'ugs ; Eichbaum preferred the powder of 

 chloride of lime, and Eauch ordinary hme, while Aubry employed a 

 mixture of Ume and caustic potash. 



Caustics were well recommended by other practitioners, but 

 their prescriptions seem to be contraxy to the rule we have laid 

 down in the beginning. However, one must not forget that the 

 tissues of the foot, especially when diseased, offer an extraordinary 

 resistance to the action of caustics ; they are, so to speak, impene- 

 trable, and the irritation they produce remains superficial, while 

 where those tissues are healthy such agents produce a deep cau- 

 terization. Again, this resisting force of the indurated tissues 

 against the actions of caustics is limited, and it is possible that 

 one, two or three applications may apparently remain inefficacious, 

 where a fourth or a fifth will give rise to extensive cauterization. The 

 result is explained by the repeated u-ritating influence of the caustic 

 agent, which, by gradually increasing the vascularity of the parts it 

 touches, increases also the means of their absorption and imbibition. 

 These facts must also be present to the practitioners mind, and 

 it is by them that he will be guided in their use, rendering them 

 at will, simply modifying, catheretic, or deep caustics. 



Nitric acid was used by Percivall and Delorme, the latter con- 

 sidering it the best means in use. Sulphuric acid has also been 

 employed, seldom alone, but mixed with agents likely to reduce 

 its effects and render its applications more convenient. CoUignon 

 and Renault recommend its reduction with alcohol ; Mercier 

 mixed it with four parts of oil of tui-pentine ; Prangc with equal 

 parts of tar, and Plass made a paste of it with burnt alum. This 

 last remedy, very simple in its foi-mula, was applied without any 

 dressing ; it has proved most excellent in a great number of cases, 

 but may give rise to too deep cauterization (Bouley, Mendel). 



Arsenious acid was much used by old horsemen, combined with 

 cegyptiacum, tui-pentine and other ingredients. Hoffmann prefers 

 the arsenite of soda in solution ; he sold his secret to the Austrian 

 government for a high price. Butter of antimony was recom- 

 mended by Huzard Sr., Prevost, and especially Huzard ; chloride 

 of zinc was preferred at the Lyons school. 



The treatment of canker by actual cauterization was indicated 



