103 
BO ENO Calis PE 12. 
is poisonous. Anyhow the quotient : UOMO must be smaller than +. 
“CaCls 
If besides 50 mgrms of uranylnitrate we add to R.-K. 200 mgrms 
of calciumchloride per litre, the circulation produces a normal action 
of the heart. If in this case the heart begins to pulsate again, the 
pulsations are quite normal from the very outset, as described above 
for the smaller antagonizing doses '). 
Because the sodium chloride in RixGer’s mixture is present in such 
a concentration as to interfere with reliable quantitative data of the 
CU0,(NOs) , 
antagonism ), I was obliged in this phase of the experi- 
Cac 
ment to confine myself to ascertaining that in RiNGer’s mixture the 
calcium chloride obviates the toxic effect of uranyl- and uranium-nitrate. 
The antagonism of UO,(NO,),, for CaCl, could be stated also in 
the anodonta fluviatilis. Quantitative data, however, could not be 
obtained with this laboratory animal, as in this case the quantity 
of body fluid was difficult to determine, so that at the pipetting 
of a uranylnitrate solution of definite strength the concentration of 
this salt in the body fluid is not known. On opening the shell the 
heart was prepared so as to enable it to continue its pulsations in 
the body fluid. On pipetting three drops of a 3 perc. uranylnitrate 
solution into this fluid a standstill ensued, which was followed again 
by pulsation after the addition of 24 drops of a 3 perc. calcium 
chloride solution. When this experiment was repeated some time sin 
succession, the cardiac action was stopped at length, and could be 
restored again only by adding some water. Through repeated pipet- 
ting of salts the osmotic pressure had obviously grown too powerful 
for a normal function of the heart *). 
J. LorB holds that ion-proteins have something to do with the 
antagonistic action of salts. He suspects the cations and the anions 
of the salts to combine with the ion-proteins. The physico-chemical 
1) Ringer has already reported that the calcium in the solution, named after him, 
may be substituted by strontium. In connection with what has been described in 
the text Mr. W. H. Jottes for the last few weeks studied the displacement of 
Calcium by strontium as an antagonist for Uranium. Strontium here also appeared 
to be a fit substitute for calcium. 
2) Cf. J. Loes, Bioch. Zeitschr. Bd. 32, S. 308. 
3) Whether sodium chloride was at all antagonized by potassium chloride and 
uranium salts could not be made out, as in that case the osmotic pressure is 
modified too much to effect a normal cardiac action. 
