The pathogenesis of hydrallantois bovis. II. Electrical potential and chemical gradients between the allantoic fluid and the maternal blood in hydrallantois and normal pregnancy.

Compared to normal pregnancy an evident reduction of the electrical potentials and electrochemical gradients was found in cases of hydrallantois without primary foetal deformity. The permeability of chorio-allantois in vitro was distinctly increased in some extreme cases of the disease. It is suggested that the pathogenesis may be a primary decrease in active transport of ions across the chorion, followed by a mechanical destruction of the micro-structure of the chorio-allantoic membranes.