The evolution of an effective program for the treatment of frostbite has been beset with unusual difficulties. For one thing, we have inherited a literature weighty with authority but largely based upon folklore and arm-chair philosophy rather than upon sound deductions from objective clinical and experimental data. It has been necessary, therefore, not only to attempt to develop new rational methods based upon controlled observations, but at the same time to overthrow erroneously conceived, but firmly established, dogma. For another thing, proper evaluation of therapy in human frostbite has been particularly difficult because of the relative dearth of material for study in times of peace and the impediments to careful clinical experimentation imposed by the exigencies of war. At the same time the variable character of the injury and the impossibility of reasonably accurate early prediction of the eventual outcome in any given case make requisite ample clinical material and its most careful study.Finally, though animal experimentation has the advantage of providing limitless numbers of subjects for study and of permitting adequate control observations, it has thus far proved to be an apparently reliable guide to treatment only in relation to the prevention of gangrene. It has added nothing to the management of the various vasomotor disturbances which constitute the commonest sequelae in man. The treatment of these sequelae in man is, to be sure, not nearly so difficult a problem as the early management of frostbite and the prevention of tissue damage. Animal experimentation, furthermore, has made possible invaluable contributions to our understanding of the functional pathology of frostbite and gives promise of adding new information about acclimatization and prophylaxis.In spite of the difficulties which have been mentioned real progress has been made in recent years in bringing about a better comprehension of the basic problem and a more rational approach to treatment. In this communication I shall limit my remarks to true frostbite and the related less severe injuries resulting from exposure to more or less dry freezing temperatures.

Cardiac septal defects, like many conditions for which no corrective treatment has been available in the past, are inadequately understood both from the standpoint of diagnostic criteria and the life history of those afflicted with these anomalies. It appears that small defects of the atrial and ventricular septa are reasonably well tolerated. Large defects, on the other hand, are associated with varying degrees of cardiac dysfunction and ultimately premature death.Once my associates and I had demonstrated to our satisfaction that we could produce experimentally large atrial septal defects which tended to remain widely patent over long periods of time and which were strikingly like those encountered in patients (1), we investigated a variety of methods for their surgical closure (2). One method seemed ideal. It involved suturing to an incision in the right atrial wall roughly parallel to the interatrial groove a half-moon shaped pocket of autogenous pericardium which could then be invaginated into the atrial cavity. The posterior wall of the pocket could be pushed against the septum so as to permit clear palpation of the defect and careful suturing of the pericardium to the rim of the defect. It could be performed with regularity and without mortality. It did not interfere with cardiac function, produced no significant electrocardiographic alterations, and could be accomplished in a dry field without loss of blood and without hazard of air embolism or intracardiac thrombosis. The grafts all survived and became firmly united with the septum. Closure was complete in nearly all instances, and in the exceptional cases there remained only an inconsequential tiny defect one millimeter in diameter. The ostia of the venae cavae and the coronary sinus were never obstructed. The method seemed eminently suitable for use in human patients.The operation as finally developed was used in two severely ill children who tolerated the procedure well (3). One has shown gratifying clinical improvement in spite of the fact that she also has a known ventricular septal defect and in spite of the fact that postoperative catheterization studies suggest the persistence of a left-to-right atrial shunt. The other child died suddenly 5 months after operation, and, to our amazement, postmortem examination showed the pericardial graft to have disentegrated and disappeared completely from the region of the defect. It then became evident that, in contrast to our experience in dogs, one could not rely upon survival of autogenous pericardium in cases of large human septal defects, presumably because of failure of sufficiently rapid vascularization of the graft. It seemed likely, however, that the operation could be at FLORIDA INTERNATIONAL UNIV on July 12, 2015 ang.sagepub.com Downloaded from

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This symposium on aneurysms and arteriovenous fistulas was very appropriately begun by a splendid homage to Doctor Rudolph Matas of New Orleans who might, better than anyone else, be looked upon as the father of modern vascular surgery. Among his many contributions was the introduction in his classic presidential address before the American Surgical Association in 1910 (1), of the first practical method for testing the efficacy of the collateral circulation before operation. He began his presentation by stating: &dquo;The surgery of the vascular system bristles with problems which still await solution but none appear to be more important or fundamental than the study of the collateral circulation in its behaviour to occluded arteries and in the means of testing its efficiency or inefficiency before permanently obstructing the more important arterial channels of the circulation.&dquo; The importance of the problem has not, I feel, disappeared with the passage of years.To be sure, methods for preserving or restoring the continuity of the affected artery by lateral suture, end-to-end anastomosis, or blood vessel transplantation have become well established procedures. Instead of being considered &dquo;uncertain, adventurous or heroic&dquo;, as of necessity they had to be in 1910, they are now looked upon as a desirable objective in the planned attack upon any aneurysm or arteriovenous fistula affecting a main arterial pathway. Though they prove remarkably effective when properly executed, it is evident that they cannot be applied in every case, and when utilized cannot always be counted upon to function well and permanently. It remains necessary, therefore, to be as sure as is possible beforehand that the collateral circulation is adequate to maintain the nutrition of the part in case blood flow through the involved artery is interrupted.My remarks will be limited to the testing of the collateral circulation in the extremities and to means of improving its efficiency. I shall not include similar problems concerned with the great vessels of the neck and trunk. The conclusions reached are based upon personal evaluation of several hundred cases before and during operative treatment, utilizing a great variety of methods. If pulsations are absent distal to an aneurysm or fistula and point clearly to obstruction of the artery at or just beyond the site of the lesion in an extremity which is not ischemic, one can assume that operative obliteration of the aneurysm or fistula will be well tolerated, provided no collateral channels are sacrificed during the procedure. This is a fact long known and well described by Delbet in 1909 (2).at University of Manchester Library on March 30, 2015 ang.sagepub.com Downloaded from