Thyroid-feeding and of Thy ro -parathyroidectomy. 105 



fluid has the same action upon the blood pressure, kidney volume, and 

 urinary secretion as extracts of the posterior lobe of the pituitary body. 



Defibrinated Blood. 



The defibrinated blood shows little action upon the rat's uterus, and no 

 appreciable difference is seen whether the blood be taken from the normal 

 thyroid-fed, or thyro-parathyroidectomised animals. 



When tested upon the blood pressure of an anaesthetised cat differences are 

 at once revealed. The blood from the normal animals causes a distinct fall of 

 arterial blood pressure accompanied by contraction of the kidneys and a 

 slowing of urinary secretion. This is succeeded by a return to normal of the 

 blood pressure, slight dilatation of the kidney and increased urinary secretion. 



Fig. 3. — Effect upon, blood pressure, kidney volume and urinary secretion (cat) of the 



intravenous injection of 3 c.c. of defibrinated blood of normal cats. 

 B.P., carotid artery blood pressure ; K., kidney volume ; U., urine drops ; S., signal ; \ 



t., time in 10-second intervals. 



The blood from the thyroid-fed cats has a similar but more pronounced 

 action, the blood pressure falls lower, indicating the presence in the blood of 

 the thyroid-fed animal of more depressor material than is present in the 

 normal animal. 



The blood from the thyro-parathyroidectomised eats, on the other hand, 

 shows a slight depressor action followed by a distinct pressor effect which 



