Attenuation

{at-ten-u-a’ shun) \attenuare, to make thin]. The act of making thin; a thinning, narrowing, or reduction of the strength or size of a substance, especially the weakening of the pathogenic virulence of microorganisms by succe ive cultivation, by exposure to light, air, heat, or other agency, or by pa ing through certain animals, so that they may be used as a vaccine to confer immunity from future attacks of the disease. A., Sanders on’s Method of, the pa ing of the virus through the system of another animal (e. g., the guinea-pig, in anthrax), so that it becomes modified in virulency. 100