Thyroid-feeding and of Thyro-parathyroidectomy. 107 



As the thyro-parathyroidectomised animals showed symptoms of tetany 

 before death it is probable that the pressor action of their blood is due to 

 the presence in it of guanidin, or allied bodies, as described by Noel Paton* 

 and his co-workers. 



Summary. 



1. Neither thyroid feeding nor thyro-parathyroidectomy affects the 

 pituitrin load of the posterior lobe of the pituitary body as tested by the 

 action of extracts upon the contraction of the rat's uterus and the blood 

 pressure of the pithed cat. 



2. There is no evidence of the presence of pituitrin in the cerebrospinal 

 fluid of the fourth ventricle in normal, thyroid-fed and thyro-parathyroid- 

 ectomised cats. 



3. The defibrinated blood of normal, thyroid-fed and thyro-parathyroid- 

 ectomised cats shows no appreciable differences in its action upon the rat's 

 uterus. The blood of the thyroid-fed cat has a greater depressor action upon 

 the circulation than has that of the normal animal. The blood of the 

 thyro-parathyroidectomised cat exercises a pressor effect upon the circulation, 

 accompanied by a contraction of the kidney and a diminution in the secretion 

 of urine. 



The expenses of the research have been met by a grant from the Kesearch 

 Pund of the Carnegie Trust for the Universities of Scotland. 



* Noel Paton, ' Quart. Journ. Exper. Physiol.,' vol. 10, p. 203 (1917). 



VOL. XCIL — ^B. 



I 



