A brief review of the work that has been done in devising methods for measuring venous blood-pressure will illustrate the general principles involved, and make easier the understanding of the new method to be described.
The veins of the hand and forearm have been those on which attention has been chiefly centered. With but two exceptions, the end sought has been a means of determining the pressure necessary to cause the collapse of one of these superficial veins. The observers have differed mainly, as will be noted, in the way in which this collapse was accomplished and the manner in which the required pressure was measured.
A contribution, dealing largely with the theoretical possibilities in the field of venous blood-pressures, was made by Frey1 in 1902. He went a step further, however, and presented an instrument for the determination of this pressure. The instrument, in brief, was so