DRESSINGS FOR WOUNDS 163 



pounds, like gasoline, kerosene, etc., penetrate and destroy the living 

 tissues. As to avenarius carbolineum, a proprietary substance, some 

 doubt has been expressed. Because of its complete absorption by 

 the wounded surface it offers many advantages. Upon dead sur- 

 faces, such as those from which decay has been removed, it is avail- 

 able, as are also carbolic acid and solutions of copper sulphate, cor- 

 rosive sublimate, etc. Upon wounds made by the removal of malig- 

 nant growths, such as crown gall, hairy-root or malignant blister 

 cankers, an active antiseptic agent is required, and for sucli use it 

 promises to be superior to copper sulphate or corrosive sublimate 

 solutions. 



(2). When effective dressings are applied to newly cut surfaces, 

 especially if these dressings are of possible antiseptic \alue, the one 

 operation of applying the dressing may be considered as relatively 

 adequate to the demands. 



136. Essential requirements of a wound dressing. — Wound dress- 

 ings should be sufficiently fluid to be applied readily under spring 

 pruning conditions — I fairly low temperatures]. They should form 

 an impervious, non-cracking layer over the surface, even though 

 large, since such a dressing will prevent the later drying out and 

 checking of the wound. These two requirements are essentially 

 antagonistic, since practically no covering within reasonable cost 

 will form an impervious covering from a single application at or- 

 dinary temperatures. Whenever the covering is not secured by a 

 single application serious danger through subsequent checks may 

 occur and thus admit disease spores. This tendency to dry out 

 limits the usefulness of paints and pastes, wliich look satisfactory 

 when applied, but dry out by midsummer. Dressings should not 

 be unreasonably costly, an objection to grafting wax, which, like 

 paraffin is also objectionable because of separating freely from the 

 wounded surface. Adhesiveness is a valuable property in a dressing 

 because it prevents abrasion. Lastly, a dressing should not injure 

 the growing tissues, though slight killing may not be as objectionable 

 as imperfect covering. 



137. Available materials for wound dressings. — Of the really 

 available materials we have chiefly preparations of asphaltum and 

 the residual tars from the distillation of wood (pitch), and from the 

 manufacture of artificial gas, gas tar. The materials used in Europe 

 under the name of "bitumen" are essentially forms of liquid asphal- 

 tum. The varnishes or proprietary preparations offered for dress- 

 ing wounds are essentially liquid asphaltum in some form. The 

 fossil "gilsonite" of California is a hardened form of asphaltum. 

 The western petroleums, which contain an asphaltum base, contrast 

 with the Pennsyhania crude oil, which has a paraffin base. An- 

 other advantage of asphaltum and gas tar materials is low cost as 

 compared with the very high cost of paints containing linseed oil. 

 The low cost of naphtha or gasoline as a solvent is much in its 

 favor, were the preparations without risk. 



