506 Captain A. G. McKendrick. [Nov. 30, 
VII. Opsonins -and Stimulins—Papers by Dean* and Marshall+ contain 
many interesting observations on the effect of dilution in opsonin and 
stimulin experiments. 
Chart 4 shows two curves: one from Dean, showing the effect of dilution 
on the opsonic index in a normal serum; one from Marshall, in the serum of 
OTA Ie 
“ 
lial 
(a) 
Zz 
0-3 
UU 
4 
Oo 
a 
07 Oo 
0-6 | 
I I FTI AE 
| 
| 
] Concentration of Serum 
i 
2 the Yo" Ya Yo. Yes | aa 
a horse, “Rich,” which had been immunised against staphylococcus, the 
treatment covering a period of about two years. 
* “Roy. Soc. Proc.,’ B, vol. 79, 
+ ‘Journ. of Path. and Bact.,’ 1908, vol. 12. 
