44 



Scientific Proceedings (62). 



artery strips recorded. Allowing for individual variations, the 

 results we obtained from a considerable number of experiments 

 showed that there was no appreciable difference in the reaction 

 of the arteries of the poisoned and unpoisoned animals. Both 

 series gave the same contraction from adrenalin and barium and 

 corresponding relaxation from the nitrite. We conclude therefore 

 that neither the vaso-motor mechanism nor the muscle tissue in 

 the larger arteries are affected to an appreciable extent by diph- 

 theria toxin. 



In poisoned animals gastro-intestinal symptoms are prominent. 

 These consist of vomiting and severe diarrhoea. A post-mortem 

 examination of the intestines and other organs shows that striking 

 changes have occurred. The pathological picture of the small 

 intestine shows marked injection of the small blood vessels, 

 arterioles and venules as well as the capillaries. The epithelium 

 shows early coagulation necrosis. In the liver the capillaries show 

 a widespread destruction. There are seen small islands of liver 

 tissue surrounded by pools of blood. In the spleen and kidney 

 also there is seen marked congestion of the terminal arteries. 



These structural changes in the different organs are highly 

 significant, and the engorgement of the mesenteric vessels would 

 offer a sufficient explanation for the low blood pressure. We have, 

 however, further studied the reaction of these vessels. A loop of 

 intestine, with its blood supply intact, was placed in a plethys- 

 mograph and connected to a calibrated recording tambour. 

 Adrenalin chlorid 1 : 10,000 in Ringer's solution was then quickly 

 run into the plethysmograph, thus bathing the intestine, connec- 

 tion with the tambour made and the change in the intestinal 

 volume recorded. The difference in the decrease in volume in a 

 normal loop, contrasted to that occurring in the intestine of an 

 animal given toxin is very striking. Calculated as cubic milli- 

 meters decrease in volume per centimeter of intestine, the average 

 decrease in normal loops was 10.17 cm -> the extremes being 15.04 

 and 5.91. The average decrease in poisoned loops was 1.8 1 cm. 

 the extremes being 4.73 and 0.57. 



In view of the marked structural changes in the smaller blood 

 vessels, and of the failure of these to respond in the normal way 

 to adrenalin we conclude therefore that the chief factor concerned 



