NERVUS SPLANCHNICUS AND ADRENALS 51 



posterior (infundibular) lobe. For the effects in general the scattered cell-collections of 



of the extract see the above original papers, the so-called ' parasympathetic ' : for special 



and Sir E. Sharpey Schafer's The Endocrine references consult, among others, Gaskell's 



Organs, London, 1916. Your own experi- Involuntary Nervous System, London, 1916, 



ment shows that the effect on the blood- and J. F. Gaskell's monograph, Fhil. Trans. 



pressure is not due to action of the extract B. vol. ccv, 1914. 



upon the vasomotor centre in the bulb, your Ohs, 35. For investigations on circu- 



preparation being decapitate. lation-times cf. G. N. Stewart, Jnl. of 



Ohs. 34. The chromaffine reaction detects Physiol, vol. xv, p. 1, 1894. 



EXERCISE YIII 



AKTERIAL PRESSURE AND PULSE; THE EFFECTS OF AORTIC STENOSIS 

 AND OF AORTIC INCOMPETENCE. REDUCTION POWER OF THE TISSUES 

 AS INDICATED BY METHYLENE-BLUE. 



[Sections in brackets may be omitted at first performance of the exercise.] 



I. See that the decapitate preparation provided is being properly ventilated 

 and in good condition. 



II. The observation required from the arterial-pressure record in this 

 exercise regards mainly a change in amplitude of the oscillations of the pulse. 

 For this the Hg manometer, ow^ing to its inertia, is less suitable than is a so- 

 called 'membrane manometer'. A simple form of membrane manometer 

 is therefore provided. Its membrane is of rubber ; its plan of construction is 

 shown in text-fig. 25. 



To get ready this manometer, clamp it by its holder to a vertical stand, open 

 the two brass taps and the screw-clip on the longer rubber tube attached to 

 one of the brass pipes leading to the capsule carrying the membrane. Fill 

 the manometer and its connecting tube with half-saturated MgSO^ solution 

 from a syringe inserted into the free end of the longer rubber tube, driving 

 the air out by the fluid introduced, and when the air is entirely expelled and the 

 fluid without bubbles issues from the short rubber tube at the other end of 

 the manometer, close the brass taps, screw tight the clamp at the syringe-end 

 of the longer rubber tube, and withdraw the syringe. 



Clamp the filled manometer, with its connecting- tube attached, to the 

 vertical standard on the kymograph ; moisten the middle of the top of the 

 membrane with a droplet of gum solution, place the small aluminium button 

 on the membrane where moistened with gum. The edge of the wedge- 

 shaped top of the button should lie transverse to the lever, which should 



H 2 



