Herman E. Pearse

Use of the Carbon Arc and Burning Magnesium as Thermal Sources for Experimental Burns

A carbon arc furnace for small burns and the burning of Mg flash powder for large burns are described. A 24-in. searchlight adapted for this purpose is described. The optical system is increased in size by using 60-in. mirrors, increasing the radiant power obtainable to 90 cal/cm/sup 2/-sec. Exposure is controlled by rate of traverse of the animal on a car through the focus. A magnesiumburning laboratory is described. The burning time is controlled by the amount of oxidizer in the blend which is obtained ready-mixed for exposure times of 0.3 to 2.0 sec. The advantages and quality of these sources are discussed. (T.R.H.)

Modification of the carbon arc searchlight for producing experimental flashburns.

During the past five years, a carbon arc source, which is basically a 24-in. Corps of Engineers searchlight with the standard parabolic mirror replaced by an ellipsoidal reflector, has been developed for use in a study of radiant energy burns in experimental animals. Accessory equipment has been devised which permits control over irradiance and exposure time, with a maximum irradiance of about 31.8 cal/cm2–sec, and a minimum exposure time of 0.1 second. This report describes the source and its operational characteristics.

The impracticability of using fascia for the gradual occlusion of large arteries

Abstract 1. 1. A method of partial occlusion of arteries with six to eight turns of heavy fascia was attempted. This amount of connective tissue was used in the hope of inducing enough scar tissue contracture to complete the obstruction. 2. 2. This method was used on the thoracic aorta of dogs in ten experiments and the abdominal portion below the renal vessels in six instances. 3. 3. With a plastic substance such as tissue strips it is difficult to judge the degree of constriction. Because of this three animals were killed by too great obstruction of the thoracic aorta. 4. 4. In four instances the arterial wall atrophied and ruptured at the site of the constricting device. Rupture occurred in from seven to seventeen days after operation. 5. 5. In the remaining nine experiments relaxation of the fascia invariably occurred. Restitution of the caliber of the lumen was partial in one month and complete in from two to three months. Resorption of the tissue bands occurred in from three to four months. 6. 6. The results of these experiments permit the conclusion that fascia is an unreliable and somewhat dangerous material to use for partial occlusion of the great vessels.