80 



EXEECISE XII 



p. 92, 1885 ; and vol. xi, p. 128, 1890, and 

 his article 'Salivary Glands', in Schafer's 

 Textbook ofFhysiol. vol. i, p. 475, 1898. Also 

 to the same for influence of atropine and pilo- 

 carpine, and indeed for all points connected 

 with the secretion part of the exercise . Con suit 

 also FsiwloS's Physiology of Digestion, transl. 

 by W. H. Thompson, 2nd edit. 1910, and E. H. 

 Starling's Becent Advances in the Physiology 

 of Digestion, Chap, iii, 1906. For the 

 anatomy of the salivary glands of the 

 cat consult Eanvier's £tude anatomique, 

 Archives de physiol. norm. etpathoL, p. 240 ; 

 Paris, 1886. 



In § IV of your exercise the flow of saliva 

 and the movement, of swallowing and move- 

 ments of tongue caused by stimulation of the 

 central end of the severed lingualis are reflex ; 

 the swallowing and tongue movements 

 certainly, the salivary flow probably, though 

 not indubitably, since escape of current 

 may have occurred on to the corda tympani. 



This you later controlled by ligating centrally. 



Together with the fibres of the lingualis 

 proper there are fibres from the corda tympani 

 [nervus intermedins), and these are some of 

 them afferent ; they contribute to the reflex 

 effect, and are competent of themselves alone 

 to produce it ; this can be shown by severance 

 of the third division of the Vth nerve in the 

 skull ; the reflex still persists then. 



In § V the lingualis nerve, after being 

 severed centrally, is used merely as a con- 

 venient structure for supporting the corda 

 tympani, which by itself alone is too minute 

 and delicate to be handled isolatedly for the 

 application of the electrodes. 



In repeating this exercise the anterior 

 belly of digastric need not be so fully de- 

 tached as before acquaintance with the 

 dissection, and the mylohyoid muscle's post, 

 edge having been found, that muscle can be 

 incised nearer the line of the ducts, and not so 

 much of it reflected. 



PLATE VI 



Observations on Salivary Secretion (Exerc. XII). 



Fig. 1. Operation, 1st stage, r, skin-flap ; t, tracheal tube ; n, ventral blade of jaw- 

 clamp. 



Fig. 2. Operation, 2nd stage ; gland ducts and corda tympani nerve exposed, f, skin-flap. 



Fig. 3. Glass cannula for duct, actual size. 



Fig. 4. Stigmatic electrode for unipolar faradization (exerc. V). w, stout wire ; PtS, 

 junction of silver wire spring with platinum terminal. 



