Abstract
The science of immunology, dealing with both the complex invading organism and the even more complex reactions of the host, had its beginnings in the pioneer observations of Jenner He found that persons who had had cowpox were immune to smallpox, and carried out a simple experiment in which he produced a cowpox lesion in a small boy and found him to be resistant to challenging with smallpox. | Since that time work has been directed toward a situation in which prophylactic immunization would either eliminate or markedly reduce the incidence of infectious diseases. | The existence of a relatively few disease entities against which the human has acquired a solid and lasting immunity stimulates research in the direction of increasing both the applications of prophylactic Immunization and the length of their effectiveness. There have been many avenues of approach. The one to be discussed herein is a study of the control of antibody production exerted by the thyroid gland.