A knowledge of the role played by the papillary muscles in the activity of the heart and especially in the closure and function of the mitral valve has become important to the surgeon involved in surgery of the cardiac valves. Current surgical techniques tend to destroy the normal relationships of the papillary muscles and there is some clinical evidence (16.20) that this is detrimental to the cardiac dynamics. Current understanding of the importance of the papillary muscle mechanism is limited by a lack of information describing the activities of the papillary muscles. It is the object of this thesis to investigate the activity of the papillary muscles and to relate these observations to an understanding of the role of the papillary muscles in atrioventricular valve function.

During the past few years, the function of the thymus gland has been greatly clarified. It is now known to play an important role in the development of immunological competence. However, less is known about that role, if any, the thymus plays in the maintenance of immune function during adult life. Because of the bearing of immune function on tissue transplantation and because of the possible role of the thymus in immune function, this gland may be of importance in a better understanding of organ and tissue rejection. Similarly, modification or removal of the thymus, with or without other treatment, may be of value in modifying the homograft rejection phenomenon. If any rational attempt, to alter homograft rejection by manipulation or extirpation of the thymus, is to be made, a more thorough knowledge of the function of the adult thymus is necessary.

Carcinoma of the breast is second in rank among all caucasian women suffering from cancer (42). First in rank is carcinoma of the uterus. In some reports (59), carcinoma of the breast ranked first; such is the case in New York state. The five year survival rate in operable breast carcinoma, by radical mastectomy is around f.fty per cent. This 5 year survival rate improves to seventy-five per cent if there are no regional or distant metastases and falls to around thirty per cent if the axillary lymph nodes are involved by metastatic disease. This tact stresses the importance of early diagnosis and treatment in carcinoma of the breast. Every year 25,000 American women die of cancer of the breast. This is a crude mortality rate of 24.6 per 100,000 for the United States (42). We cannot seem to lower this figure with any known method of diagnosis or treatment.

Almost one hundred years ago Paul Langerhans (1) described the pancreatic islet cells. Another 50 years had passed before its physiological significance had become clear, following the studies of Laguesse (2). On the basis of histological observations, particularly referring to profuse vascularization of the islets, Laguesse suggested in 1893, that islet cell have an endocrine function. The classical experiments of Banting and Best (3) in 1922 lead to the identification of the hormone insulin and consequently to the treatment of diabetes. According to present knowledge, insulin is secreted by Beta cells. It has been shown that the insulin content of the splenic portion of the dog's pancreas is much higher than the duodenal portion.

Revascularization of the ischemic myocardium is one of the major concerns in the field of experimental surgery. The increasing disability and death from obliterative disease of the coronary arteries, which all too frequently attacks men in the prime of life whose other organs are still intact and healthy, has stimulated widespread interest in the field of medicine to produce some means of increasing the blood flow to the ischemic myocardium. The causative factors in the genesis of coronary occlusive disease is still far from clear.

Evidence from paleopathology indicates that cancer is a very ancient disease. Preserved relies of prehistoric times reveal wide geographic and zoologic distribution of malignancy. Dinosaurs of the Mesozoic period are said to have shown signs of cancer, and other evidence of its antiquity (Sambon cited by Haddow) (68) are to be found in the treasures of the pyramids, from the Etruscan tombs, from Peruvian mummies and from the cuneiform tablets of the library of Nineveh. The earliest medical record known to man (94) is the "Edwin Smith Surgical Papyrus". This anonymous relic of antiquity is generally regarded by historians as having been originally written in the Egyptian Pyramid Age in the Old Kingdom (3000- 2500 B.C .), although speculation by Breasted and Cooper (16) suggest that this document may form part of the teachings of the oldest known physician, Imhotep, the 'patriach and sage of primitive medicine' (94) who lived in the thirteenth century B.C.

The present hospital mortality rate for myocardial infarction is reported as 47%, and when shock occurs it is said to be above 85% regardless of the type of therapy. Most of these patients die in left heart failure. It is obvious that present treatment of myocardial infarction is inadequate and a new approach is required. The answer appears to lie in some type of support to the heart which could adequately maintain systemic and coronary circulation, while the damaged myocardium recovers from its injury. With such assisted circulation surgical correction could be accomplished in isolated lesions and collateral circulation might develop in diffuse disease.

This thesis describes investigations of a purely experimental treatment for severe burns, and seeks to relate the benefits of such treatment to the accepted pathophysiological principles of burn sickness. In particular it dwells on the eftect of hypothermia on the scalded rat in terms of mortality, development of shock, and postburn toxicity. The work was stimulated by certain observations made by Dr. N. G. Foy, reported in his Master of Science thesis of 1963, at McGill University. [...]

It has recently become increasingly obvious that the present means (endoscopy and urography) of evaluation of early or minimal cases of lower urinary tract obstruction may be totally inadequate. Endoscopic examination of the lower urinary tract may reveal trabeculation of the bladder, which could be secondary to outlet obstruction, but with no direct evidence of such obstruction. On the other hand, the bladder wall may appear normal in the presence of urethral obstruction. Similarly, urography does not provide the meansn of adequately evaluating such cases. [...]

Recent projects in this laboratory have been devoted to the study of a number of problems related to acute experimental pancreatitis. The first of a series of findings in this field of endeavour was the demonstration that a uniformly fatal form of acute haemorrhagic pancreatitis could be induced in the dog. With this tool in hand, further experiments implicated the release of bradykinin in the pathogenesis of the clinical manifestations of the glandular insult. It was simultaneously shown that the proteinase inhibitor Trasylol (FBA Pharmaceuticals) could favourably alter the mortality rate of animals inflicted with this disease and appreciably decrease the amount of active bradykinin released in the course of experiments. [...]