26 



INTERNAL SECRETION 



logical action between nervous matter and the infundibular 

 part of the pituitary." A striking result in some of our experi- 

 ments was the causation of very extensive irregularities in the 

 blood-pressure curve after injection of brain extracts. Schafer 

 and Moore had previously noted a lowering of blood-pressure 

 on injection of brain extracts, but they did not lay any stress 

 on the observation. Professor Osborne and the author worked 

 out fully the effects of nervous-tissue extracts, and found that 

 extracts made from all parts of the nervous system produce a 



marked temporary fall 

 of arterial blood-pres- 

 sure, which can be ob- 

 tained after section of 

 both vagi and after 

 administration of suf- 

 ficient atropin to abol- 

 ish vagus action (see 

 Figs. 1 to 5). We came 

 to the conclusion (con- 

 trary to that of Mott 

 and Halliburton) that, 

 although choline was 

 present in small 

 amounts in the ex- 

 tracts, the depressor 

 effect was not due to 

 the presence of that 

 substance. The reason 

 for this view was that, 

 whereas after the ad- 

 ministration of atropin 



to an animal, choline always produces a rise of blood-pres- 

 sure, these extracts, on the contrary, always produced a fall 

 (see Figs. 3-5). 



Figs. 1 and 2 show the effects of extracts of brain and spinal 

 cord upon the blood -pressure, the volume of the intestinal wall, 

 the volume of the hind-limb, and upon the contraction of the 

 auricle and the ventricle of the heart. 



Figs. 3, 4, and r> show the difference in action between 



nervous-ti in extracts and choline in an atropinized animal. 



Vine. 'hi and Shern found that a depressor substance can be 



Fio. 1. Dog. A. C.E., morphine, curare, arti- 

 ficial respiration. Loop of intestine in air 

 plethysmograph. Injection of 1-5 c.c. de- 

 coction cat's brain (Osborne and Vincent). 



