PHYSIOLOGICAL ACTION, AND ANTAGONISM. 
225 
Contracture produced by barium is enormous (Plate 9, fig. 24, a-g). When the drug is 
locally applied its curve resembles greatly that produced by veratria (Plate 9, fig. 24, b). 
It appears to us to be an interesting fact that an inorganic element and an organic 
alkaloid should have such a similar action. Their action coincides also in the modifica¬ 
tions which it undergoes by heat and by potash. The barium contracture, like that 
caused by veratria, is abolished by cooling the muscle down, or by heating it con¬ 
siderably above the normal. The contracture may be permanently removed by 
cooling down, so that it does not return when the muscle is again raised to the 
normal temperature. Like the veratria contracture, however, it is abolished much 
more certainly by heat (Plate 9, fig. 24). There is a more marked tendency for 
the barium contracture to relax suddenly than that caused by veratria. It is also 
more easily abolished by repeated stimulation. 
In regard to the effect of these drugs on contracture, the same differences are to be 
observed between their action when injected into the circulation and when locally 
applied that we have already mentioned in regard to the active curve. In the 
accompanying diagram we have arranged some of the more important substances 
Contracture. 
Increased. Diminished. 
Altitude of Curve. 
Lowered. Heightened. 
Active Curve. 
Lengthened. Shortened. 
belonging to the alkalies and alkaline earths so as to show their action upon muscle 
graphically. It will be seen that they tend to form a series, the two ends of which 
present some points of approximation, ammonium appearing to form a connecting link 
between barium and potassium. 
It will be noticed that the substances here do not arrange themselves according to 
their atomic weight, nor yet according to their atomicities. We hope, however, to be 
able to consider this point more fully at a future time. We subjoin a table showing 
the relative position of the elements in regard to their action on motor nerves and 
muscles. 
2 G 
MDCCCLXXXIV. 
