460 ON THE PHYSIOLOGICAL ACTION OF CASCA BAEK. 



minute, three or four respirations occurring during each cardiac 

 diastole. Notwithstanding the very slow action of the heart, 

 the pressure may remain as high as 165 millimetres of mercury, 

 a fact which indicates that the arterioles are in a state of 

 extreme contraction. After the heart has ceased, the pressure 

 falls very slowly. Slight pulsations of the ventricle occasionally 

 occur when the thorax is opened. 



17. Small doses do not seem to increase the excitability of 

 the peripheral ends of the vagi to electrical stimuli ; moderate 

 and large doses paralyse these nerves. 



18. After injection of casca into tlie veins of an animal com- 

 pletely narcotised by chloroform, electrical irritation of the 

 central end of the divided vagus of one side, the other remain- 

 ing intact, is followed after a short interval by marked slowing 

 of the pulse, fall of blood-pressure and increased oscillation. 



19. When injected into the veins of a cat after division 

 of the spinal cord opposite the second cervical vertebra, the 

 blood-pressure rises to a greater height than is attained under 

 other conditions. 



20. When in the rabbit the sympathetic has been divided in 

 the neck on one side, subsequent injection of casca into the 

 jugular vein produces pallor of the recently congested ear of the 

 side en which the division had been made. 



21. When locally applied to the web of a frog's foot tem- 

 porary slowing of the circulation was observed, but no alteration 

 in the diameter of the blood-vessels. 



When injected beneath the skin of the back of a frog it pro- 

 duces no visible effect on the vessels of the web. 



22. It does not appear to possess any special action on reflex 

 excitability. 



23. In moderate doses it increases the secretion of urine at 

 the same time that it raises the blood pressure. Further doses 

 diminish the secretion, while they raise the pressure yet more ; 

 and at the time when the pressure reaches its maximum the 

 ■secretion of urine is entirely arrested. When the pressure 

 begins to fall the secretion of urine again commences. The 

 Ririne collected after the recommencement of the secretion was 

 not albuminous. 



