890 
shows a smooth curve; more often we find a clonical after-con- 
traction (fig. 7). Reeords of this kind are obtained in cases where 
igs 7: 
in ordinary conditions the tonus is not quite high enough to permit 
of a elonus. But as soon as a tap on the tendon elicits the muscle 
twitch and the tonus reflex, the tonus sufficiently increases to render 
a short clonus possible. This last disappears as soon as the tonus 
reflex in finished. If we can in some way diminish the tonus before 
the reflex is obtained, the increase of tonus caused by the reflex may 
be insufficient for a clonus. In such a case we should be able to 
provoke either a tonic or a clonic after-contraction, only by lowering 
or inereasing the tonus beforehand. Resting the foot, slight active 
bending of the knee diminishes the tonus in the quadriceps ; supporting 
the knee and slight passive bending increases it. 
Fig. 8. 
Fie. 8 gives a record on which the first reflex shows a clonic, 
the second one a tonic aftercontraction, which were obtained in 
this way. With all patients of this kind the tonus is not quite 
sufficient to admit of a persisting clonus. Only under the most 
favourable circumstances, as after prolonged exposure to a low 
temperature, and much care in arranging the most favourable 
