( 553 ) 
the muscles of the paralyzed leg smaller than in those of the normal 
leg in a dog after section of the ischiadicus. That the normal 
leg continues performing voluntary movements, is no objection, there 
being * no ground to assume that then creatine is formed. But the 
muscles of the paralyzed leg degenerate. Although, we killed the 
animals already three days after the section of the nerve, yet every 
time the paralyzed gastrocnemius appeared to be of a smaller weight 
than the normal one. Nothing is known about the formation and the 
destruction of creatine in degenerating muscles. Of no less importance 
seems to be the change in the circulation of the blood alter section 
of the nerve, in consequence of which the removal ot creatine from 
the muscles may be altered in a quite incalculable degree. 
On account of these objections we thought of entirely giving up 
the attempt to inquire into the influence of the muscletonus in warm¬ 
blooded animals, and of being obliged to occupy ourselves on.y with 
cold-blooded vertebrates, in which without any- trouble the blood- 
circulation can be shut out (in muscles of invertebrates no creatine 
has been found; they were not fit for our purpose accordingly) when 
my colleague Prof. R- Magnus drew our attention to a means ot 
bringing muscles of one half of the body of a cat into strong tonus, 
whilst the corresponding muscles on the other side, without any 
disturbance in the action of the centrifugal nerves and m the circu¬ 
lation of the blood, remain slack. 
Sherrington ') has found that, when in deeply narcotised dogs, 
monkeys, cats, rabbits or cavias, the action of the cerebral hemi- 
spheres is excluded by a section in the region of the hindmost 
corpora qnadrigemina, after a short time the so-called “decerebrate 
rigidity” develops itself, a long continuing tonic contraction of dehmte 
muscle-groups, among which especially the extensors of the extre¬ 
mities and the retractors of the head and the neck are the chief. 
This state of things is dependent on impulses which arise in the 
periphery, and by centripetal nerves are led to the spinal cord. That 
is why the stiffness does not arise in those parts of which the 
corresponding dorsal roots are severed. 
Now Prof. Magnus had the kindness to operate upon five cats in 
such a way that one foreleg was brought in tonus two, three hours 
at a stretch, whilst the other leg remained slack. The perfectly nar¬ 
cotised animal, the narcosis being brought about first by means of 
ether, then by means of chloroform, after section on the left side 
of the hindmost roots of the four or five lowest cervical nerves and 
of the two highest thoracic nerves was decerebrated. &oon, the right 
*) Joum. of Physiol. Vol. XXII, p. 319. 
