Influence of Age upon Response to Meningococcal Endotoxin in Rabbits

A comparison was made of the response to meningococcal endotoxin in young (4-7 weeks) and more mature (10-12 weeks) rabbits, with the following results: 1. Young rabbits were relatively unaffected by a single intravenous injection of endotoxin, in doses more than 50 times the amount which caused prostration and death in older animals. 2. The febrile reaction to small doses of endotoxin was not significantly different in the 2 groups of rabbits, 3. An intravenous injection of colloidal iron saccharate enhanced the lethal effect of endotoxin in all rabbits, and eliminated the difference in susceptibility between young and older animals, 4. The generalized Shwartzman reaction, with bilateral cortical necrosis of the kidneys, occurred in a high proportion of young rabbits after 2 intravenous injections of endotoxin. This reaction could not be elicited in more than 10% of the older rabbits.