(10 ) 
Physiology. — J. W. LANGELAAN on: “Further investigations on 
muscle-tone.”’ (Abstract). (Communicated by Prof. T. Prace). 
On the assumption of a muscle-reflex are on which the muscle- 
tone depends, it was proved in a previous series of experiments }),- 
that there is a Jogarithinic relation between the value of the successive 
tonicity-quotients and the corresponding increments of the charge. 
The distensibility was taken as measure of the muscle-tone. From 
this the analytical expression was derived, which represents the 
increase in length of the not visibly contracting muscle as function 
of the increase of the charge. 
For this relation was found: 
l= Ap + Bp lgn. p, 
and it was pointed out that this held good only for the interval of 
the increase of the charge, over which the experiment ranged. 
These experiments made on frogs, were afterwards extended to 
cats, whose spinal cord was cut at a high level. The m. triceps 
surae was chosen to record distention curves, according to the method 
shortly described in my previous communication. The operations 
were done under ether narcosis, but as soon as the medulla was 
cut, no more narcotic was given. The severing was always followed 
by spinal shock, but within a few hours the muscles proved, at least 
partly, to regain their tonicity. 
Also in this case the distention curve appeared to be represented 
by the same analytical expression, but the variation of charge during 
the experiment was far more considerable. As an illustration we 
subjoin four tables, representing the measurements of four curves. 
1) Proc. Kon, Akad. van Wetensch, Amsterdam, Sept. 29th 1900. 
