No abstract

Radiant energy of wavelengths shorter than 3200 1 was excluded by Pyrex glass in producing cutaneous bums in the pig with the carbon arc so\irce. The 50^ effective exposures for burns so produced were conrpared with those escposiires required with the caxbon axe source alone at 0.5 sec. exposxire times.It was found that excltision of the shorter ultraviolet wavelengths increased the 50?^ effective exposiire of radiation required to produce 1+, 2+, 3+ and k+ bums. Ultraviolet radiation had a most marked effect in producing erythema (l+ burn); the 5^5^ effective exposure was increased two-fold with its exclusion. No effect was observed in the 50^ effective exposxire for the threshold of complete transepidermal damage Judged by depth of damage microscopically produced with or without the short wavelength radiation.

Burns produced on the pig by the carbon arc sotirce alone and modified by two filters one eliminating all wavelengths below 33li-0 A, the other below 617O K at expos-ore times of 0.5* 1.0, 2,0 and k.O sec. were graded by surface appearance in the following manner. 1+ bums are erythematous lesions, 2+ bums show in the mildest form small spots of whiteness scattered over a red background. As the severity increases the spots become confltient. 'When an area of one cm^ appears completely white, the laboratory grade of a 3+ b\im is reached. Each grade of severity was fxirther divided into mild, moderate and severe subgroups. The bums were also evaluated histologically by depth of damage. It was foimd that a bum as judged by surface appearance in the grades of 1+ moderate to 3+ mild showed similar microscopic changes in each subgroup regardless of the expostire time or the wavelength distribution of energy used, A table is given which will serve as a guide to the depth of damage which will be foxmd in a given bxirn when graded by its stirface appearance for exposure times of 0.5 to k^O sec.

No abstract

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