1043 
by me more elaborately in the Biological Section of the Society for 
promoting Physiology, Physic, and Surgery (Genootschap ter bevor- 
dering van Natuur-, Genees- en Heelkunde). Here I observe only 
that analogous observations were made by me after the poisoning 
of the frog’s heart both with veratrine and antiarine. 
The groups of Luciani were often followed by separate systoles 
of the ventricle (crisis of Luciani). There upon stagnation of the 
ventricle. It can likewise occur that the crisis does not set in at all. 
LANGENDORFF and Ourwa. are of Opinion that the variations of 
rhythm form the transition to the periods of Luciani. I can by no 
means share this view. It is true that in my method variations of 
rhythm proceed the periods of Luciani, but they do not oecur in 
the latter part of the 2rd stage and, consequently, they cannot form 
the transition to the 3'd stage. They occur exactly im the beginning 
of the 2nd stage. 
They are indeed variations between the 2°¢ and the 1s stage of 
poisoning *), 
Amsterdam, 13 Nov. 1916. 
Physiology. — “On the Analogy between Potassium and Uranium 
when acting separately in contradistinction to their antagonism 
when acting simultaneously.” By Prof. H. ZWAARDEMAKER. 
(Communicated in the meeting of February 24, 1917.) 
Physiologically there is some analogy between potassium- and 
uranium-salts. Both arestro ng poisons, ‘the first for the heart, the 
second for the kidneys’). Again, in small doses they very largely 
aid the functions of these organs*). The automatically beating frog’s 
heart, when fed artificially is a very suitable object to watch this 
useful action, as it is not fed along capillaries, but through lacunae 
penetrating everywhere from the cavity into the wall. 
For artificial circulating fluids salt-solutions are used, so diluted 
that they possess the normal osmotic pressure and, moreover, contain 
“next to each other 2 molecules of calcium chloride 1 or 2 molecules of 
1) A more explicit paper follows in the Archives Neerlandaises de Physiology de 
Vhomme et des animaux. Tome I. 3e livraison p. 502 (1917). 
2) Woroscuitsky, Arb. a. d. pharmakol. Inst. in Dorpat. Bd, 5, 1890. 
8) Moreover, in the concentration of !/, on, uranium is conducive to alcoholic 
fermentation as well as to the growth of the tubercle-bacillus and the Bacillus 
pyocyaneus. (Vide BecqvereL and others in G. R. t. 154 ff.), 
