It is known that contact of a solution hydrogen peroxide (H₂O₂) with open living tissues or with tissue fluid, for example, after a skin injury causes a violent reaction with the release of large amounts of oxygen that produces large amounts of foam. It is a fact that the hooves of horses, cattle, pigs and other species of mammal (also human nails) are an extremely strong material and have a strong mechanical junction with the sur-rounding tissues. The junction between the hard claw and the soft tissues of a digit in the region of the perioplic segment (limbus) and the dorsal border (margo) is a delicate living stratum. A 3% solution of H₂O₂ was used externally on the healthy hooves of varying species of mammal as a means of measuring the sensitivity of the dermo-epidermal tissue. External positive reactions as seen by the formation of foam after addition of this solution of hydrogen peroxide to the healthy digits of horses, cattle and man are presented in the photographs. These reactions confirm the delicate nature of these living junctions in quoted places only. The junction of hoof and soft tissue is very strong physically but it appears to be quite weak biologically (as a halve open tissue - sensible on H₂O₂) and may act as a potential route of infection for various microorganisms, which can cause lameness and thus become a large problem on cattle farms. This weak biological junction in healthy claws may have an important role in the etiology of inflammation in this anatomical region as well as in the development of digital dermatitis in cattle, especially on farms where environmental, nutritional, technical and hygienic conditions are poor.

33-39