IN the course of our experimenits upon the lungs we have spent much time in studying the question of the innervation of the pulmonary vessels, and as the final result of this work have devised a method which we bring forward as a general test for the existence of a nerve supply to any set of blood vessels. The investigation arose from the results we obtained when repeating those experiments of Bradford and Dean and of Fran-ois Franck from which they concluded that the pulmonary blood vessels

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... e supplied with vaso-constrictor fibres. Although we were able to confirm most of the experimental results they had recorded, we were unable to agree with them in concluding that the effects they observed could only be explained on the supposition that the pulmonary vessels were supplied with constrictor fibres and were therefore under nervous control. We obtained evidence that in all the methods they adopted cardiac effects had not been entirely eliminated, and that while in most cases cardiac acceleration had been excluded, cardiac augmentation was still present 1. In order to solve the problem it therefore became necessary to devise some method which wouild entirely exclude all possibility of a cardiac change. We first studied the rate of flow of blood through these vessels during an artificial perfusion with blood at constant pressure, in the hope that the nerves, if present, would remain excitable for some time after death. We showed that by taking a set of vessels known to possess 1 We propose to deal fully with these experiments in a future communication.