CITRUS DISEASES. . 75 



rapid healing, is sterilization of the surface to kill any spores which 

 may be present. For this purpose either corrosive sublimate or 

 Bordeaux paste may be used. 



These substances, it must be understood, are not permanent in 

 their effect, and must be shortl}- followed by m permanent wound 

 dressing. In the case of pruning" wounds, or those produced by 

 causes other than fungi, the first application of a disinfectant is 

 not usually necessary. 



There is not at present available an ideal wound dressing, but 

 several which are in general use, or which are recommended for use, 

 will be mentioned. 



The substance most commonly used in Porto Rico for this pur- 

 pose is Carbolineum Avenarius, a propietary compound. Because^ 

 however, of the difficulty of making sure of obtaining the genuine 

 article (other types of earbolinium being, so far as known, injur- 

 ious), and the unsatisfactory features of the substance itself, its use 

 is not recommended. It is quite possible for injury to follow its 

 use; in fact, such cases have been reported. 



Common white lead or white-lead paints are also in common use. 

 These are far from satisfactory, although of some value if the pre- 

 cautions given in a following paragraph are adhered to. There have 

 also been used to some extent various propietary wound dressings. 

 These are fairly satisfactory but their use should be preceded by 

 the use of a disinfectant in all cases. 



Of all the many substances at present available for this purpose 

 in Porto Rico, gas tar stands first. This is a product of the destruc- 

 tive distillation of coal in making gas, and can be obtained locally 

 at a relatively small cost, an important point in its favor. Gas tar 

 is given second rank by tree surgeons and others who have studied 

 the question of wound dressings. Certain asphaltum compounds are 

 considered best, but are not available here. Tlie tar has been under 

 trial at the Experiment Station with most satisfactory results, which 

 fact, combined with field observations in groves where it has been 

 used and the general favorable reports given it by experts in the 

 North, leads us to recommend it alone for this purpose. No cases of 

 burning have been reported or observed. As a general rule the only 

 treatment necessary is a good coating of gas tar carefully brushed 

 on after the wound has been thoroughly cleaned and prepared. It 

 will penetrate a short distance into the living bark, but no more 

 tissue will be killed than dries out normally in untreated wounds. 



Finally, there must be considered the renewal of the dressings. 



