372 Dr. J. O. W. Barratt. [ Dee! 5, 
Table X.—Comparison of Complement Fixation in presence of Inactivated 
Serum obtained (a) from mice with tumours and (0) from a normal 
mouse. The contents of each tube after standing at 37° C. for 1 hour 
were added to sensibilised red cells obtained from 0-02 c.c. of a 23-per- 
cent. suspension of the red cells of the rabbit and the mixture kept, 
with occasional shaking, at 37° C. for a further period of 2 hours. 
No oe pe ap © | Inactivated | Inactivated Nicase Hemolysis at end of— 
of serum of | solution TOTEN Gs serum of tumour 
: normal mouse with 
tube. two normal | of sodium one ae con extract. 
| mice. | chloride. : ; 30 mins. 120 mins. 
C.C. Cc, | G.G. | c.c. c.c. 
af 0-010 0-100 | — | = — Slight? Slight 
2 0 020 0:090 | — — — Marked Nearly 
| | complete 
3 0 ‘030 0-080 | = — — Nearly Complete 
| complete 
4, 0 :020 0°055 | 0:005 = 0°025 | Very slight Slight 
5 0 040 0-035 | 0:005 — 0 °025 Slight Complete 
6 0 :060 0°015 | 0:°005 - 0-025 Marked Me 
Tumour Mouse 1. 
i 0 020 0°055 | — 0 005 0°025 | Very slight | Very slight 
8 0 -040 0°0385 | — 0-005 0 °025 “ Slight 
9 0 ‘060 0:015 | -— 0 °005 0°025 Slight | Marked 
Tumour Mouse 2. 
10 0 020 0-055 = 0 005 0:025 | Very slight | Slight 
11 0-040 0 °035 — 0 -005 0 :025 Ss | es 
12 0-060 0-015 — 0-005 0°025 | Slight Marked 
Tumour Mouse 3. 
13 | 0 -020 0-055 —— 0:005 | 0:025 Not Not 
recognisable | recognisable 
14 0 :040 0 °035 == 0 °005 0°025 | Very slight Shght 
15 0 -060 0-015 | — 0-005 0-025 Slight ‘Marked 
when tumour mouse serum is employed indicates that this serum, in reality, 
contains a considerably greater amount of amboceptor corresponding to 
the antigen used than does normal serum. Experiments of the kind 
recorded in Table X were repeated with the same and with other tumour 
mice sera. Altogether, the sera obtained from six mice with well developed 
tumours were employed, and in each case two complement fixation tests 
were made. With one exception, all the tests gave a similar positive result 
such as is shown in Table X. The exception occurred when the observa- 
tion made with the serum of Tumour Mouse 1 was repeated; in this case 
