The influence of the sympathetic nervous system on capillary permeability.

1. The influence of the sympathetic nervous system on capillary permeability was studied in cats. The dye penetration from the blood through the synovial membrane was tested by perfusing the two knee joints, one of which was deprived of its sympathetic nerve supply by unilateral lumbosacral sympathectomy. 2. In confirmation of previous experiments, it was found in a great majority of experiments that, in spite of marked vasodilatation, the dye excretion was considerably reduced on the sympathectomised side. 3. A large amount of experimental evidence, supporting directly or indirectly, my views, has been reviewed. 4. A permeability factor under the influence of the sympathetic nervous system has been postulated; its character and mechanism is still unknown. 5. Further unpublished experiments seem to support the view that increased blood supply is associated with decreased vascular permeability.