178 Messrs. 8. G. Shattock and L. 8. Dudgeon. [Dec. 21, 
serum is due to their greater secreting activity, ve, to their increased 
production of the converting substance; and that when melanin or bacteria 
are presénted in vitro, this interaction is set: going, or, rather, restarted in the 
drawn. blood. 
Observation. 
CasE.—Empyema. 
1 vol. of blood, ; 
1 ,, citrated salt suspension of melanin. 
Four tubes were prepared, and incubated for different periods, with the 
following results :— 
LS miMUbes |. Ate. cease oad 9 granules of melanin in 50 cells 
loti eee eke chee 21 3 a 
OD MOUTS dines. eee skes neat eee 36 i - 
AA Wee st icc caesecacea tener 76 * bs 
In such an observation it is impossible to determine whether the pro- 
gression is due to further formation of opsonin or to the increased time 
allowed for the continuance of phagocytosis. 
When bacteria are used in place of melanin, this progression may be more 
highly pronounced, as is shown in the three following observations :— 
CaszE.—Acute cellulitis ; temperature, 102° F. 
1 vol. of patient’s blood, 
1 ,, citrated salt suspension of colon bacilli. 
Incubated 20 minutes ............ 50 cells contained 126 bacilli. 
1 vol. of patient’s blood, 
1 ,, citrated salt suspension of colon bacilli. 
Incubated 30 minutes ............ 50 cells contained 195 bacilli. 
CasE.— Urinary infection due to colon bacillus ; untreated with anti-serum or vaccine. 
1 vol. of patient's blood, 
1 ,, citrated salt suspension of colon bacilli. 
Incubated 20 minutes ............ 50 cells contained 115 bacilli. 
1 vol. of patient’s blood, 
1 ,, citrated salt suspension of colon bacilli. 
Incubated 30 minutes ............ 50 cells contained 165 bacilli. 
Casre.— Urinary infection due to colon bacillus ; treated with anti-serum and vaccine. 
1 vol. of patient’s blood, 
1 ,, citrated salt suspension of colon bacilli. 
Incubated 20 minutes ............ 50 cells contained 116 bacilli. 
1 vol. of patient’s serum, 
1 ,, citrated salt suspension of colon bacilli. 
‘Theabaved oO minutes 2 joraeseee 50 cells contained 196 bacilli. 
