149 



In correlating- (his resnlt with the well-known observations of 

 Chiari and Januschke ^), according to which the process of conjnnctival 

 intlammation may be ai-rested bv instillation of a CaClj-solulion, we 

 are led to suppose that a definite concentration of Oa-ions exercises 

 a constricting influence upon the vessels and at the same time a 

 coagulating action upon the vascular wall. It appears then that both 

 these actions are neutralised by K. 



That the contracting and the coagulating action may coincide, 

 is substantiated by the observations on the intluence of oxygen. 

 SÉvERiNi'j found that oxygen brings about contraction of the vessels; 

 while GuNZBUHG*), reports that a potassium-free Ringer's mixture, 

 which in other cases always caused a-dema, did not cause it when 

 the mixture was saturated with oxygen. Fiom this it seems probable 

 that vascular contraction coincides with decrease of permeability of 

 the vessel-ivall not only with a definite concentration of Ca-ions, 

 but also under the influence of oxygen. 



As regards the inhibition of vascular constriction through the 

 addition of KCl to the mixture NaCl 0,67, + CaCl, .6 aq. 0.01»/,, it 

 appears (hat the minimal required concentration of KCl is about 

 KCl 0,004 7,. 



S U M M A R Y. 



The described researches, of which a detailed report appeared 

 in the Biochemische Zeitschrift*), may be summarized as follows: 



1, When perfusing the frog's leg with an aqueous solution of 

 NaCl and CaClj, potassium may be absent in the circulating fluid, 

 without oedema being evoked. The circulating fluid, however, should 

 contain a definite concentration of calcium-ions. NaCl 0.67o CaClj . 

 6 aq. 0.0077c ^^i" serve our purpose here. When using CaCl, . 6 aq. 

 0.006 7» oedema will arise. This will occur also when to the first- 

 named mixtui'e 0.01 7o KCl is added. This phenomenon finds an 

 explanation in the fact that the coagulating action of the Ca-ions is 

 counteracted by the antagonistic K-ions. 



2. That GuNZBURG wanted potassium in his solution to prevent 

 oedema is to be ascribed to the fact that he used an excess of cal- 

 cium-ions. The arrest of oedema in Gunzbürg's experiments is. 



^) Churi u. Janusghke, Arch. f. exper. Pathol, u. Pharmakol. 65, 120/126, 1911. 



^ LuiGi Sevérini, „Ricerclie sulla innervazione dei vasi sanguigni". Perugia 



Boncompagni et Gie (See Bayliss: ,Pi'inciples of General Physiology", i915. p. 534. 



^) GuNZBURG, I.e. 



*) Rudolf J. Hamburger, Bioch. Zeitschr. 129, 153, 1922. 



