354 Dr. W. M. Bayliss. On Recoprocal [Jan. 20, 
attributed to excitation of the vaso-constrictor centre.* Fig. 9 shows, indeed, 
that this statement is correct. Vaso-constriction in the intestine is seen 
coincident with the rise of blood-pressure. 
Supposing that the first dose was not too small, say 5 milligrammes per 
kilogramme, the injection of a further dose is followed by a fall of arterial 
pressure with a peripheral vaso-dilatation. Each subsequent dose is accom- 
phyA hr 
ly iy wn 
Fig. 9.—Effect of first injection of strychnine. Upper curve, arterial pressure. Lower 
curve, volume of intestine. 
panied by the same effect, until complete paralysis of the centres ensues. 
Fig. 10 is a tracing of the intestinal volume. 
Now what is this fall of pressure due to? There are several reasons for 
the belief that it is an excitation of dilators. In the first place, the action of 
strychnine in general is exciting, rather than inhibitory, so that it is quite 
probable that dilators should share in the general excitation.f Secondly, when 
* Vide Cushny, ‘Pharmacology,’ 4th ed., p. 201, 1906. 
t Vide Cushny, loc. cit., p. 202. 
