W. F. Hahvev and a. M''Kkndkick 
79 
accentuate the dififerences from normal or the fluctuations from an original value, 
due to the presence of infection. The affected part is massaged, or a Bier's baudage 
put on above a joint for half an hour, so as to flush it with the retarded blood. 
If after this procedure the opsonic index shows the fluctuations which might be 
expected from the entrance of either antibodies or antigens into the blood stream, 
the diagnosis becomes clear. The following examples will illustrate this point : 
(1) 
April 8, 1908 
Index 
To Gonococcus 
To Tubercle 
Bacillus 
Before Bier 
h hour after 
5 hours after 
20 hours after 
1-40 
1-24 
1-36 
1-84 
1-06 
•89 
•90 
1-00 
(2) Effect of Masscuje. B. tuberculosis. 
Before -87 
^ hour after •95 
3 hours after ^97 
21 hours after 1-19. 
(3) Effect of Exercise. B. tuberculosis, 25. 5. 08. 
Before -87 
Just after '97 
7 hours after 112 
19 hours after ri5. 
One of the defects of these illustrations is that we are ignorant of the effects 
produced on the variability of normal serum indices by, say, the application of 
a Bier's bandage to a normal joint, massage or exercise. The point is one, however, 
which could be easily settled. 
We proceed now to consider how far opsonic indices are comparable with one 
another. This is a much more difficult question to answer offhand. It would 
seem certain that if they are, it can only be under some strict limitations of 
technique. We are dealing in this determination with a number of varying 
factors. Some of the chief possibilities of variation and problems are : — 
(1) The Leucocyte. Number in unit volume; degree of admixture of red 
blood corpuscles ; variation in vitality ; degree of settling. • 
(2) The Bacterium. Number in unit volume, i.e. the concentration of the 
emulsion; virulence; whether laboratory culture or autogenous; degree of agglu- 
tination by the sera used ; age of culture ; dead or living ; whether diplobactei ia 
or larger aggregations are to be regarded as single ingestions or more. 
(3) The Serum. Whether, with the quantities of serum emulsion and leucocytes 
used, we have, so to speak, the opsonin and antigen present in exact combining 
