Introduction
Attempts to discover safe and effective means of inducing active immunity against measles have extended episodically over a period exceeding 200 years. Francis Home of Edinburgh initiated these studies when in 17581 he scarified the skin of susceptible children and applied cotton pledgets soaked in the blood of patients acutely ill with measles. In this way he hoped to induce an immunizing infection unaccompanied by severe respiratory complications that in his time were of major concern.Because the earlier work on active immunization has often been reviewed, I shall restrict this summary to a consideration of investigations on live attenuated virus vaccines which have been reported since 1954, when the application of modern methods of tissue culture provided tools for a fresh approach to this old objective. In so doing I shall first recapitulate researches done in our laboratory and then briefly refer to similar work of others