346 
Transactions of the Royal Society of South Africa. 
that represented by the smallest amount in the series which produced 
complete lysis (complete lysis occurring when one dose is left free). The 
number of doses deviated by the serum and emulsion separately was 
deducted from the number of doses absorbed by the serum and antigen in 
combination, and the result represented the exact degree of deviation 
produced apart from the inhibitory effects of serum and bacillary emulsion. 
Thus any inequality in the anti-complementary action of different antigens 
was allowed for. 
By this method, in which the amount of complement deviated by varying 
amounts of antiserum along with a fixed quantity of bacillary antigen is 
Table XXIII. — Lys7s of O'b c.c. 5 jjer cent. Suspension Ox Blood + 5 Doses 
Immune Body. 
Bacillary 
emulsiou. 
Antiserum 
to Strain I, 
Al (B. No. 
71 McC). 
Doses of complement. 
(.Complement 
deviated by 
emulsion 
alone. 
0 025 c.c. 
2 D. 
4 D. 
7 D. 
12 D. 
20 D. 
2 D. 
1 D. 
Strain 1,A1 
0-2 c.c. 
0 
0 
0 
0 
F. tr. 
Com. 
Com. 
012 
0 
0 
F. tr. 
F. tr. 
Dist. 
Com. 
Com. 
0-04 „ 
0 
Trace 
Dist. 
Dist. 
Mkd. 
Com. 
Com. 
002 „ 
0 
Dist. 
Mkd. 
Mkd. 
Com. 
Com. 
Com. 
Strain 1,A2 
0-2 c.c. 
0 
0 
0 
0 
0 
Com. 
Com. 
012 „ 
0 
0 
0 
Trace 
V. mkd. 
Com. 
Com. 
0-04 „ 
0 
F. tr. 
Mkd. 
Com. 
Com. 
Com. 
Com. 
002 „ 
Trace 
Dist. 
V. mkd. 
Com. 
Com. 
Com. 
Com. 
Strain 2, Al 
0-2 c.c. 
0 
0 
0 
0 
0 
Com. 
Com. 
012 „ 
0 
0 
0 
Mkd. 
Mkd. 
Com. 
Com. 
0-04 „ 
0 
F. tr. 
Trace 
Mkd. 
Com. 
Com. 
Com. 
0-02 „ 
0 
Trace 
Al. com. 
Com. 
Com. 
Com. 
Com. 
0 025 c.c. antisernm alone deviated 1 D. of complement. 
tested, it is possible to precisely differentiate B. typhosus from B . lyaratyphosus 
A and B. In one of my own experiments 0*0002 c.c. of an anti-typhoid 
serum along with a strain of B. typhosus (not that used for immunisation) 
deviated over seventeen doses of complement, while with B. jjaratyphosus A 
0*025 c.c. of the serum was required to produce a deviation of ten doses 
and 0*0002 c.c. produced practically no deviation. Thus by careful 
quantitative comparisons it is possible to establish a precise species 
differentiation between certain allied organisms. In the case of B. typhosus 
the relative specificity is for the species. 
Besidts observed luith antisera to A types 4, 1 and 3. — In the case of the 
antiserum to strain 1, A4 {B. Grilnthal), over fifteen doses of complement 
were absorbed by the combination of 0*001 c.c. of antiserum and the strain 
