1. Periarteritis nodosa is a specific infectious disease which is transmissible to the rabbit.
2. The lesions induced in rabbits are identical with those occurring in man and consist of exudative and degenerative processes within the walls of the smaller arteries resulting in aneurysmal formations and thromboses.
3. The microorganism inducing the disease is capable of going through a Berkefeld N filter and is therefore to be classed with the group of so called filter passers.