1341 
It is well-known that this substance cheeks the O-consumption. 
When applied in traces, which renders the check imperfect, KCN 
was found to acceierate phagocytosis considerably. On the respiratory 
centre the effect of slight quantities of KCN is the same: Violent 
respiratory movements set in. Greater quantities cause paralysis in 
both cases. 
4. Also as regards carbonic acid an analogy is found between 
_ phagocytes and respiratory centre. Traces of CO, were discovered to 
promote phagocytosis, whilst greater quantities decreased it. As we 
know the irritability of the respiratory centre is likewise increased 
by CO,, but the centre is paralyzed by an excess of CO, in the 
blood. 
5. The facts and views set forth here, supply an obvious answer 
to the question which formed the starting-point of the present in- 
vestigation: why do traces of chloroform and other fat-dissolving 
substances cause an acceleration of phagocytosis ? 
The numerous researches of VeERWORN and his pupils on narcosis 
have established the fact that narcotics such as chloroform have the 
property of impeding the O-consumption by the cells (spinal centres, 
nerve-fibres, amoebae etc.). Now it is obvious that as long as mere 
traces of chloroform are acting, only part of the available oxygen 
will be rendered useless, in other terms, the blockade of the oxygen 
will be incomplete. And then the phagocytes are in the case of the 
experiments mentioned sub 1, where partial removal of oxygen by 
nitrogen or hydrogen causes an acceleration of the phagocytosis. 
This acceleration gradually passes into a retardation in proportion 
as the store of oxygen of the cell becomes more exbausted; an 
exhaustion which sets in quickly when, for instance by the admini- 
stration of larger amounts of chloroform, the oxygen-consumption 
has fallen to a minimum or has ceased altogether. 
hb. The explanation given sub 5 of the acceleration of phago- 
eytosis by traces of chloroform is in perfect agreement with the 
fact that in the first stage of chloroform-narcosis the irritability of the 
respiratory-centre is increased. Likewise the excitement-stage is ea 
plained, which manifests itself at the beginning of the narcosis, and 
which hitherto none of the narcosis theories have so much as attempted 
to explain. (Cf. note 3 p. 1326). 
Here too, with the higher nerve-centres, the explanation must be 
sought in a heightened sensitiveness in consequence of an incipient 
