346 Dr. W. M. Bayliss. On Reciprocal [Jan. 20, 
sympathetic, although it has been shown by Fletcher* that a few fibres for 
the tip of the ear run by way of the ramus vertebralis of the stellate 
ganglion and the third cervical nerve. If the cervical sympathetic is cut, 
there is, then, a small part of the ear left in connection with vaso- 
constrictors. I do not think that these fibres play any part in the reflexes 
obtained under experimental conditions. The ear soon becomes cold and 
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Fig. 2.—Excitation of dilators in pelvic nerves in depressor reflex. Upper curve, arterial 
pressure. Middle curve, volume of penis. Blood-pressure zero, level of 
excitation-signal. ‘The second excitation of the vagus central end was without 
effect on the penis, probably following too closely after the preceding one.t 
bloodless under anesthetics and curare, so that only reflex effects of con- 
siderable magnitude are shown in the plethysmographic curve. In fig. 3 
the result of exciting the central end of the vagus on the opposite side, 
which, in this case, contained more depressor fibres than the depressor nerve 
itself, is shown. The cervical sympathetic having been cut, the effect must 
be due to dilator nerves, apart from the problematic inhibition of Fletcher’s 
fibres, above mentioned. Since the dilators in question are possibly 
* ‘Journ. of Physiol.,’ vol. 22, p. 259, 1898. 
t It will be noticed that in many of the plethysmographic curves given in the following 
pages small waves appear during the period of excitation. These are merely due to the 
fact that the exciting coil was placed on the table of the kymograph. The interrupter 
was in action only during the excitation-period and the slight shaking of the writing 
lever diminished the friction between it and the smoked paper so that the respiratory 
waves were traced. This is of use in that it serves to mark out exactly the period of 
excitation. 
