350 Dr. W. M. Bayliss. On Reciprocal [Jan. 20, 
considerable number of experiments were of a negative character. At the 
same time those in which positive results were obtained were precisely such 
cases as would be expected to possess tone of dilators, viz., those with high 
temperature and blood-pressure ; moreover, the effect was generally obtained, 
if at all, early in the course of the experiment. 
Fig. 6 is an instance from the ear of the rabbit. The cervical sympa- 
thetic being cut, the vaso-motor supply was limited to dilators, with the 
exception of the few sympathetic fibres to the tip of the ear already 
referred to. 
In fig. 7 an attempt was made to increase the tone of the dilator centre by 
Ih, 
MWA Mi Wi Wy 
gt 7 
Fig. 6.—Vaso-constriction by Fic. 7.—Inhibition of dilator tone. Upper curve, 
inhibition of dilator tone. -volume of hind-leg. Lower curve, arterial pressure. 
Median nerve excited. Zero, 40 mm. below time-signal. Uppermost signal, 
Upper curve, arterial pres- excitation of depressor. Middle signal, excitation of 
sure. Zero, 30 mm. below median nerve, twice. 
time-signal. Lower curve, 
volume of ear. Time in 
10 sec. 
excitation of the depressor. In order to lessen the effect of the fall of 
arterial pressure, the peripheral end of the cervical sympathetic was excited 
along with the depressor; this latter, however, did not seem to be very 
active, as judged by the change of arterial pressure. It did, apparently, 
increase the effect of excitation of the median nerve, shown by the difference 
between the first and second excitations on the tracing. The small effect of 
the later one may also be due to its following the previous one at too short. 
an interval of time. 
The tongue was disappointing, as before, showing mere passive changes. 
