196 The Influence of Gravity on the Circulation. [Dec. 13. 



13. That if the heart is affected, as by chloroform or cnrare poison- 



ing, the restoration of pressure is incomplete, and it is possible 

 that the heart may be stopped altogether by the inrush of a 

 large quantity of blood, caused by too rapid an application of 

 pressure on the abdomen. More work would be thrown upon 

 the heart than, in its impoverished condition, it could 

 perform. 



14. That vagus inhibition and cardiac acceleration are subsidiary 



compensatory mechanisms in the feet-up and feet-down 

 positions respectively. 



15. That chloroform rapidly paralyses the compensatory vaso- 



motor mechanism, and damages the heart. 



16. That ether, on the other hand, only paralyses the compensatory 



vaso-motor mechanism very slowly and when given in 

 enormous amounts. 



17. That the vaso-motor paralysis induced by these anaesthetics 



lasts for some considerable time after the removal of the 

 anaesthetics. 



18. That chloroform can, by destroying the compensation for 



gravity, kill the animal, if it be placed with the abdomen on 

 a lower level than the heart. 



19. That elevation or compression of the abdomen immediately com- 



pensates for the vaso-motor paralysis produced by chloroform. 



20. That compression or elevation of the abdomen, coupled with 



artificial respiration and with squeezing of the heart through 

 the thoracic walls, is the best means of restoring an animal 

 from the condition of chloroform collapse. That these 

 results agree entirely with McWilliams', and are opposed to 

 those of the Hyderabad Commission. 



21. That the feet-down position inhibits respiration, and the feet-up 



position accelerates it. 



22. That these respiratory results probably depend upon the stimu- 



lation of sensory nerve endings by changes of tension brought 

 about by the alterations of position, because the results are 

 abolished by dividing the vagi. 



23. That in the feet-down position the respiration is thoracic in 



type, and the abdomen is retracted ; in the feet-up position the 

 respiration is diaphragmatic and the abdomen freely expanded. 



24. That these types of respiration tend to compensate for the 



effects of gravity on the circulation, for the retraction of the 

 abdomen in the feet- down position mechanically supports the 

 abdominal veins, whilst the thoracic inspirations aspirate 

 blood into the heart. In the feet-up position the full and 

 free expansion of the abdomen withdraws all obstacles to the 

 compensatory dilatation of the abdominal veins. 



