1337 
purpose, (the effect of artificial venous congestion on the phago- 
cytosis of bacteria) determine the amount of CO, which accelerates 
phagocytosis when only serum is used. 
At any rate it may now be looked upon as an established fact 
that, as regards carbonic acid, the phagocytes behave exactly like the 
respiratory centre. For the respiratory centre is also stimulated by 
slight quantities and paralyzed by greater ones. 
As we know, potassiumeyanide has a highly stimulating effect on 
the respiratory centre before paralysis sets in. A violent dyspnoea 
manifests itself. 
It is all but certain that this symptom must be connected with 
the property this substance has of obstructing the oxygen-consump- 
tion of the cells. This becomes manifest, for instance, when we 
note the effect of KCN on muscular contraction. Even if to the 
blood with which the muscle is supplied, oxygen is added in an 
ample degree, traces of potassiumcyanide lower the oxygen-consump- 
tion considerably. 
What may be the effect of potassiumeyanide on phagocytosis ? 
The following tables will supply an answer. 
TABLE XL 
Effect of KCN on phagocytosis. 
Serous ee Phagocytosis 
0 | 12.1 9, 
1 : 1000 0 
{> 2000 | 0 
1: 5000 | 6.6 0/, 
1: 10.C00 dn 
1: 50.000 23.9 
1 : 100.000 18:25, 
From this table it appears that in a concentration of 1 to 1000 
and also of 1 :10000, KCN has had a noxious, but on the other 
hand in weaker concentrations, a favourable effect on phagocytosis. 
The following table contains experiments also with weaker con- 
centrations. 
