568 Prof. C. 8. Sherrington. On Reciprocal _ [Nov. 3, 
has always pressed an exactly opposite view.* By Ashert the question has 
been tested in another case by pitting depressor stimulation against asphyxial 
stimulation of the vasomotor centre: there also the results he concludes 
confirm those already given by the experiments on vagus-accelerator and on 
constrictor-dilatator antagonism, __ 
Similar questions arise in regard to the reflex inhibitions expressed by 
skeletal muscles. Here the seat of the inhibition is central. The skeletal 
muscle attached by means of its motor nerve to the centre expresses by 
contraction the excitation of the motoneurones of that centre and by 
relaxation or by restraint from contraction the inhibition of those moto- 
neurones. In the following experiments I have chosen as field for collision 
of the opposed influences, excitatory and inhibitory, the motoneurones of the 
vasto-crureus muscle. Of the various afferent arcs acting on this field I 
have selected two whose reflex influences are of diametrically opposed 
direction. Of these, one causes flexion of the knee, the other extension. 
The former was excited by faradisation of the central stump of the 
ipselateral peroneal nerve severed at the knee, the latter by similar 
faradisation of the contralateral popliteal nerve likewise severed at the 
knee. The vasto-crureus, with its nerve and blood supply and attachments 
intact, was isolated as described in previous papers.{| The femur was fixed 
by a strong clamp close above its condyles. All nerves of the opposite leg 
were severed to exclude reflex movement there which might confuse the 
result. The animals (cat) were decerebrate, decerebration being performed 
under deep chloroform-ether narcosis. For faradisation two Berne coils 
with secondary values graduated in Kronecker units were employed. In 
the secondary circuit containing the electrodes there was intercalated in all 
cases a resistance of 100,000 ohms in order to steady the stimulation values 
for the nerve-trunk. 
In one respect the mutual antagonism of these reflex influences acting on 
this preparation differs from that described as obtaining in the antagonisms 
mentioned previously. The difference is as follows :—When both the 
afferent nerves are stimulated fairly strongly the ipselateral exerts pre- 
ponderant influence over the contralateral.§ This preponderance is evidenced 
in two ways: (a) The muscle, while contracting under the excitatory 
influence of the contralateral reflex, on fairly strong stimulation being 
applied to the ipselateral afferent nerve forthwith relaxes completely so as 
* ‘Nerfs d. Cour,’ Paris, 1905, ‘ Nerven d. Herzen,’ Berlin, 1907. 
+ ‘Zeitschr. f. Biol.’ vol. 47, p. 87, 1905. 
{ Sherrington, ‘Journ. of Physiol.,’ vol. 36, p. 185. 
§ Sherrington, ‘ Integrative Action of the Nervous System,’ 1906, p. 224. 
