1883.] Chemical Constitution, Physiological Action, Sfc. 327 



sometimes diminished by yttrium and calcium. It is diminished by 

 didymium, strontium, and beryllium. The duration of contraction is 

 increased by barium, calcium, strontium, yttrium, and erbium. It is 

 unaffected, or slightly diminished by beryllium, didymium, and 

 lanthanum. 



Contracture is in creased by barium, calcium, strontium, yttrium, 

 and beryllium. The contracture produced by barium is enormous, 

 resembling that produced by veratria, as the authors have shown in a 

 former paper. It is, like that of veratria, diminished by heat, cold 

 and potash, and may be abolished by these agents. It is not so well 

 marked when the drug is injected into the circulation as when 

 locally applied to the muscle. 



The action of some of the more important of those drugs can be 

 graphically represented by a spiral, the terminal members of which 

 .-are potassium and barium, and these two are to a certain extent con- 

 nected by ammonium as an intermediate link. 



The alteration effected in the action of the different members of 

 these groups on muscle by the subsequent application of another, is 

 next discussed, and it is shown that the effect of one substance upon 

 muscle may be increased or diminished by the application of another. 

 One of the most curious points is that two substances having a 

 similar action may, instead of increasing, neutralise each other's 

 effect. 



Potassium shortens the lengthened muscular curves produced by 

 barium, calcium, strontium, sodium in large doses, and lithium, and 

 reduces the contracture which they cause. Sodium in large doses 

 lengthens the curve and increases the contracture of the normal 

 muscular curve, and it adds to the length of the long curves caused 

 by calcium and strontium. The veratria-like curve of barium is 

 counteracted by almost all the substances which produce a shorter 

 curve than itself. There is remarkable antagonism between barium 

 and rubidium. Rubidium in large doses produces an elongated curve 

 with enormous contracture almost like that of barium. This abnormal 

 curve is reduced to the normal by barium, and if this is applied to a 

 greater extent than is sufficient to antagonise rubidium, it again 

 produces the prolonged curve characteristic of the barium itself. In 

 the case of calcium and strontium, which have a similar action in 

 prolonging the curve, we find no antagonism ; the one tending rather 

 to increase the effect of the other. Some relations are pointed oufc 

 between the atomic weights of antagonising elements. Although 

 the data are too limited to draw from them any general rule, the 

 . authors think that they may possibly lead by-and-by to some useful 

 result. Thus, calcium reduces the barium curve to the normal before 

 it causes its own peculiar curve. This may be looked upon possibly 

 as the result of the union of the barium and potassium having 



