An attempt has been made to analyze the factors involved in the development and localization of the dermal pneumococcic lesion in the rabbit.
The character and quantity of the edema fluid which forms during the early phases of the lesion are intimately concerned in its development and spread. It contains an antithrombic substance, probably derived from the pneumococci, and delayed coagulation probably facilitates its movement through the tissue. The direction of spread in the skin is determined by gravity, and the fluid finally localizes in the more dependent regions. The distance that the pneumococcic lesion travels and the local tissue characters have much to do with the amount of fluid that accumulates.
Studies are also reported of some factors which alter the rate of spread of the edema fluid. An acceleration in rate occurs when H. influenzae is used as an associative infective agent with the Pneumococcus.