34 Messrs. Dudgeon, Panton,and Wilson. Influence of [Aug. 2, 
leucocytes, or the bacteria; secondly, how far this action is specific for 
various organisms belonging to the same family; and thirdly, whether the 
inhibition of phagocytosis is due to absorption of complement by the 
endotoxin. 
In the present series of experiments the technique adopted has been the 
same as described in the preliminary report, with the exception that the 
bacteria were allowed to grow for a longer period of time, so as to obtain a 
more abundant growth for the preparation of the endotoxin. In every case 
the bacterial deposit was alternately frozen by means of solid carbon dioxide 
and thawed, as by this method a more potent extract was obtained. For 
each group of experiments a fresh extract was prepared. 
Ls the action of the Endotoxie Substance on the Leucocytes ? 
Equal parts of the extract and washed human leucocytes were mixed 
together and incubated for one hour at 37° C.; they were then centrifugalised 
and the supernatant fluid pipetted off. One volume of the treated leucocytes 
was added to equal volumes of serum and bacillary suspension and incubated 
for 15 minutes at 37° C. In every instance the leucocytes were found to be 
unaffected, since as marked phagocytosis occurred when the leucocytes had 
been submitted to this treatment as in the control. The following brief 
experiment will serve to illustrate this point :— 
] 
No. of No. ot 
bacilli in | _y sooayti 
'50 celle, | Ranecemen 
: cells. 
A. (Normal leucocytes + saline) + normal serum+ B. Achard ........064. 328 i 
95 3 + 5 +B. typhosus .....000000: 132 4 
B. (Normal leucocytes + Achard extract) + normal serum + B. Achard 300 2 
BS f “9 + ss + B. typhosus 138 4 
C. (Normal leucocytes + typhoid extract) + normal serum + B. Achard 369 0 
3 a * + 7 + B. typhosus 156 8 
Ts the action of the Endotoxic Substance on the Bacteria themselves ? 
For this series of experiments a given volume of extract was added to an 
equal volume of bacteria and incubated for one hour at 37° C. The mixture 
was then centrifugalised at very high speed until a clear supernatant fluid 
was obtained; this was pipetted off and an equal volume of normal saline 
was added to the deposit and the whole thoroughly mixed. A volume of this 
final bacterial mixture was then added to equal volumes of normal serum 
and leucocytes. The result of these experiments was to show that no action 
took place between the organisms and the endotoxic substance, and that 
