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SummaryExperiments on monkeys show that in this primate, temporary occlusion of the blood supply to the legs does not cause any signs of shock until the circulation through the damaged leg is reestablished. Then severe shock ensues even before any significant amount of fluid can be lost from the blood into the damaged area. This observation is incompatible with the dehydration theory of shock.Blood taken from the vein of an extremity which was damaged by temporary occlusion of its blood supply does not prove more toxic when assayed on the adrenalectomized mouse than blood coming from an intact extremity. This observation is incompatible with the toxic theory of shock.Experiments on the rat and cat indicate that the sugar concentration of the blood coming from a damaged extremity is significantly below the corresponding values in normal venous blood, conversely the hemoglobin and N.P.N. concentration is above normal in blood which passed through the damaged area. It appears that damaged tissues remove cert...

SummaryDiabetes was prevented in 9 of 10 rabbits given alloxan by temporary occlusion of the celiac and superior mesenteric arteries. The remaining animal developed moderate, delayed diabetes with mild histological changes in the islets of Langerhans.Severe hypoglycemia was observed in several of the rabbits which failed to develop diabetes and which failed to show any histological change in the islets of Langerhans or the liver when examined at 2 to IS days.These experiments indicate that alloxan diabetes is pancreatic in origin but suggest that the hypoglycemic phase is either extrapancreatic in origin or may be produced by the action of very small quantities of alloxan insufficient to produce detectable changes in the islets of Langerhans.

Summary1. Compression of the coronary vessels and immediately adjacent tissue as descrilml caused pain without exception, sometimes salivation, vomiting in one case, a disturbance of respiration, “acute dilatation” of the heart and various changes in the electrocardiogram. Symptoms have not been produced by localized compression and tearing of the myocardium or pericardium. This may be due to a high threshold of problematical pain endings in the normal cardiac muscle and pericardium.2. Severance of the vagi has not interfered with transmission of pain impulses in 2 dogs.3. Removal of the left stellate ganglion has prevented the transmission of pain impulses in 2 dogs but salivation occurrecl in one of the 2.4. A prompt fall of blood pressure occurred in all acute experiments on compression of the coronary vessels as described. Section of the vagi usually prevented this fall in blood pressure.5. Fall of blood pressure, cardiac dilatation and cardiac irritability are increased by moderate cyanosis (anoxemia).

In a previous report1 on the action of the vagus in bulbar anaemia induced by temporary occlusion of the head arteries, it was shown that, after division of both vagi, the heart rate does not change during the anaemic rise of blood-pressure, but remains at whatever maximum rate was attained after vagotomy.It has been thought desirable to find out the effect on heart rate during the cardio-vascular response to bulbar anaemia, of removal of the stellate ganglia through which run the accelerator fibers to the heart. Accordingly, in a series of cats, after a control occlusion had been done according to the usual method,2 the stellate ganglia were excised and further occlusions were done. Following is a typical result of such an experiment.It is evident from the above table, that, with the accelerators eliminated, the vagi are over-active in holding the heart rate down. Under such conditions, recovery of the medulla after the circulation has been restored to the head arteries may, at times, be somewhat difficu...

Pike1 has shown that in the spinal cat there is a certain reflex element concerned in the maintenance of blood-pressure, by the fact that section of the dorsal roots of the spinal nerves in the thoracic region causes a fall of about 10 millimeters of blood-pressure. Wickwire2 has demonstrated that section of the dorsal roots of the spinal nerves from C5 to L2 does not abolish the compensation of heart rate to high and low blood-pressures.A series of experiments was made to see whether division of the dorsal roots of the spinal nerves would affect the cardiovascular response to bulbar anemia, produced by temporary occlusion of the arteries to the head.3 Laminectomy was done through the thoracic region, and the head arteries were isolated as usual. The blood-pressure rise in a control occlusion of the head arteries was then recorded, and as soon as recovery was initiated, the dorsal roots were divided in the thoracic region, and occlusion of the head arteries was repeated. Such difference in response as was...