894 
positions of the lower limbs, we may be able to produce a damped 
clonus or perhaps even a permanent clonus. 
We have now to consider another group of records in which the 
after-contraction forms the most important and conspicuous part in 
the whole reflex. 
Fig. 9 gives an exceedingly protracted after-contraction of nearly 
5 second’s duration. Clinical observation shows that this is not a 
case of spinal automatism. In testing the knee-jerk we find that the 
leg is extended in the ordinary way, or perhaps a trifle longer, 
and falls down as in a normal reflex. But we see and feel, that 
the tendon remains in a state of maximal tension and that the 
muscle itself retains its condition of increased tonus. Then the tonus 
disappears slowly and gradually and only after several seconds the 
original condition has returned. That we have indeed a tonus 
variation of excessive magnitude before us and not a contraction 
strictiori sensu, may be seen from fig. 10. This record was obtained 
from the same patient suffering from diplegia cerebralis pseudobulbaris 
and shows two knee-jerks in succession, the second being elicited 
before the first had entirely subsided. The second jerk shows, in 
exactly the same way as the first a maximal simple twitch, 
whereas afterwards the tonus was still more exaggerated. As the 
second jerk gives a record which in this patient must be regarded 
as a customary one, a real contraction ought to be considered as 
highly improbable. Neither is the hypothesis of an automatism very 
alluring, as this patient did not show any other typical spinal auto- 
matie movement. Finally the clinical examination showed, that in 
the almost paralysed patient all changes of the muscle tonus dis- 
appeared very slowly, and agreed absolutely with the after-con- 
tractions of the knee-jerk. 
In another patient with diplegia cerebralis the knee-jerk produced 
quite a series of interesting movements, as will be seen in the 
records of fig. 11—13. In fig. 11 we find that the initial twitch 
can be followed by a protracted tonic aftercontraction, on which 
either clonic movements with a rhythm of 8 per second are super- 
posed or not. In other circumstances, principally determined by the 
position of the limb, and the way of supporting it during the exa- 
mination, I could get a series of automatic movements with a 
rhythm of about 2°/, per second. At the same time the cionus of 
8 per second remained more or less visible (fig. 12). By a slight 
change in the way of supporting the knee it was possible to 
obtain much longer duration of the automatic movements (fig. 13); 
the more rapid clonus disappeared completely after a few seconds 
59* 
