348 Dr. W. M. Bayliss. On Reciprocal [Jan. 20, 
purposes, the spinal cord had been transected at the third lumbar segment 
27 hours previously. The hind-limbs were, therefore, in connection with 
vaso-motor centres by vaso-constrictor fibres only. The first excitation in the 
figure is of the central end of the vagus; a fall of arterial pressure follows, 
with considerable increase of volume of the limb. Between the two parts of 
the figure the abdominal sympathetic was cut on the side of the limb under 
neh, 
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\ 
Fic. 4.—Dilatation by inhibition of constrictor tone. Upper curves, volume of hind-limb 
of dog. Lower curves, arterial pressure. Time in 10 sec. Zero of blood- 
pressure, 24 mm. below time-signal. 
observation. Expansion of the limb is shown, due to cutting off tonic con- 
strictor impulses. The central end of the vagus was again excited, a similar 
fall of arterial pressure being produced, but this time accompanied by passive 
diminution of volume of the limb. This result is, however, not always to be 
obtained ; it appears that, at allevents under experimental! conditions, tone of. 
