196 



Transactions of the Canadian Institute. 



[Vol. VII. 



previously stated, the aorta must be compressed during firm abdominal 

 pressure. 



Tracing XIV. — 1/3.— Dog under Atropin. 7 Vertical. 8 Struggling, q Horizontal. Lower line 

 is respiratory tracing. 



Tracing 14 shows the effect of posture on an animal in which the 

 vagi had been paralysed by atropine. At 7 it was placed vertical, with 

 very little fall in pressure. The effects are practically the same as 

 when the vagi are intact. 



Division of the Spinal Cord at various levels. 



This always produces a great lessening in the compensation for the 

 feet-down position. 



Tracing XV'.— 3/10. —Spinal cord previously divided opposite 8th dorsal vertebra. 12 Vertical. 

 13 Horizontal. 14 Head down. 



Tracing 15 illustrates this point. The cord had been divided 

 opposite the eighth dorsal vertebra, and the pressure in the horizontal 

 position fell somewhat. When the animal was placed in the vertical 

 feet- down posture at 12, the pressure fell rapidly and threatened to 

 actually become negative. The pulse did not hasten, in fact, slowed 

 somewhat. The pressure rose about the ordinary amount in the feet-up 

 posture, as shown at 14. 



