86 



EXERCISE XIII 



torn. 1, p. 110; Paris, 1842) and Meltzer 

 {Arch. f. Physiol, p. 212 ; 18S ) examined 

 the inhibition of the respiratory rhythm 

 which accompanies deglutition. That rhyth- 

 mic reflex deglutition along with respiratory 

 arrest and closure of the glottis is evoked by 

 faradizing the central end of the superior 

 laryngeal branch of the vagus was noted 

 by the elder Waller and J. L, Prevost, 

 1870 [Archives de physiologic nor male ef 

 pathologique, torn, iii, pp. 185 and 343 ; 

 Paris). 



Obs. 67. Careful study of the effect on 

 the respiratory rhythm of severance of the 

 vagi in the neck was first undertaken by 

 Legalloisj 1812 {Experiences sur le prlncipe 

 de la vie, p. 160 ; Paris), the discoverer of 

 the bulbar respiratory centre. On the whole 

 question of the respiratory effects of sever- 

 ance and stimulation of the central ends of the 

 vagi consult the masterly paper by H. Head, 

 1889 {Jnl of Physiol, x. 1-70, 279-90). Cf. 

 also E. Sharpey Schafer, C.R. Soc. d. Biol. 

 Paris, 1918, 1135. 



EXERCISE XIY 



VASO-DEPKESSOR AND CARDIO-INHrBITORY REFLEXES ; THEIR DISSO- 

 CIATION BY ATROPINE. VASOPRESSOR REFLEX PROM AFFERENT 

 LIMB-NERVE. 



I. See that the decerebrate preparation provided is in good condition; 

 if necessary the ' blower ' should be attached. 



II. Arrange the induction apparatus for faradic stimulation ; the 

 kymograph, &c., for arterial-pressure record. Set the Kinger-Locke fluid 

 warming to 38° C. Have ready a needle-syringe for intravenous injection. 

 Some atropine sulphate, 1 per cent, sol., is provided in a small test-tube. 



Obs. 68. III. Operation. Place preparation supine with all four limbs symmetri- 



Vaso-depressor cally extended. Fix the symphysis of the mandible in the mandibular 



reflex of the n ^ x ./ 



depressor clamp. Expose the right (or left, according to preference) vagus and 



sympathetic in the upper part of the neck by the dissection already 



described (exerc. IV, PI. II). Before separating them at all expose them 



forward well beyond the level of the thyroid branch from the carotid, 



following them by turning aside laterally the lowest piece of the 



submaxillary gland, and reaching the superior laryngeal branch of the 



vagus nerve. Look for a small nerve running along with the vagus 



and sympathetic. This may not be easy to detect. One way is to lift 



the whole conjoined vago-sympathetic and note whether it is not 



