Co 
12 Dr. W. M. Bayliss. On Reciprocal [Jan. 20, 
to call it, a state of adsorption. We are justified in supposing that the same 
change occurs in the state of normal excitation. If, under these conditions, 
a change takes place in the colloids of such a nature that diminution of 
surface occurs, coagulation for example, adsorbed electrolytes will necessarily 
be set free. Macdonald also assumes that the opposite process occurs in 
inhibition. Excitation, then, is associated with increase, inhibition with 
diminution, of electrolytes. Now in fig. 27 let us imagine that the synaptic 
membrane at a will allow ions to pass from the cell-body to the arborisation, 
but not in the reverse direction, while that at ¢ allows ions to pass from the 
arborisation to the cell-body only. On arrival of a nerve-impulse, with its 
setting free of electrolytes, at c, these latter can pass freely into the dilator 
neurone D, causing excitation in it; the constrictor neurone C will not be 
excited, since the ions are unable to pass into it. Since ions have passed 
out of c, more will travel along the fibre to take their place, and since the 
membrane at a allows their passage from the cell-body of the constrictor 
neurone C to the fibre F, it is conceivable that such takes place, thus 
diminishing the concentration of electrolytes and producing inhibition in the 
constrictor neurone. | 
On this hypothesis the action of strychnine would be to make the 
membrane at a permeable to electrolytes in the same direction as c, so that 
excitation of both cells occurs. 
This is the barest possible outline of a conceivable explanation of the 
phenomena. No doubt, much modification would be necessary. Moreover, I 
do not at present see how to account for the chloroform effect on these lines. 
Expressed shortly, the action of strychnine is to convert the minus signs 
at a and d into plus signs: that of chloroform is to convert the plus sign 
at b, and probably that at c, into a minus sign. According to the hypothesis 
sketched above, this statement seems to imply more than a mere summary of 
the experimental facts, as might appear at first sight. 
Fig. 28 is a diagram of the probable relations in the Lovén reflexes. 
There is a rather interesting point in connection with these reflexes. 
When an afferent nerve of a limb, eg., the median, is excited, vaso-con- 
strictors to the kidney are excited; on the other hand, when the central end 
of a dorsal root of the kidney area is excited, these same constrictors are 
inhibited. Is the “final common path ” in the two cases the same? Or are’ 
‘there two distinct sets of constrictors? I hope to be able to decide this 
question in the work on the Lovén reflexes, already in hand. 
In respect to the action of strychnine, it will be remembered that it was 
found by Sherrington that inhibition was not converted into excitation in all 
cases of reciprocal innervation. Those muscles used to maintain the normal 
