34
goat-antisheep-serum, with fresh sheep serum as complement, and different propor-
tions of sheep serum (55°C.) as the inhibiting ,agent.
It will be seen that in the presence of 72 per cent. sheep serum (55°C.) twice
as much complement was required for complete lysis as when the serum was re-
placed by 0.85 per cent. salt solution, 54 per cent, inhibited in a lesser degree, 36
per cent, scarcely at all, while 18 per cent. on the other hand had an auxilytic
influence.
A similar result is produced by the heated serum of an animal homogenous
with the erythrocytes used, when a heterogenous serum is the lytic agent.
For example, when fresh man serum was used as the lytic agent against sheep
erythrocytes, a concentration of 0.11 gave complete lysis. When 60 per cent,
heated sheep serum was present three times that quantity of man serum gave only a
trace of lysis. Sixty per cent. fresh unheated sheep serum also inhibited lysis
considerably, but less than th.e heated serum.
When sheep serum which had been decomplemented by the action of heated
rabbit erythrocytes was used as the inhibiting agent, it was found that heating from
3 0 ′
— 9 0
′ c a u s e d i t t o i n h i b i t m o r e s t r o n g l y t h a n t h e s a m e d e c o m p l e m e n t e d s e r u m
unheated. Heating for 120′ o n t h e o t h e r h a n d r e d u c e d t h e i n h i b i t o r y p o w e r
slightly. The serum heated for 15 ′ only was more strongly inhibitory than the
unheated serum.
Similarly, when heated sheep serum which had not been previously decom-
plemented was employed, no difference was observed in the inhibitory power
between 30′ and 90′ heating. Heating for 120′, however, reduced the inhibition.
Tests made of the viscosities of a serum heated for different periods showed a
definite increase in serum heated to 55°C. for 30 ′ over fresh serum: Further heat-
ing- for 120′ did not seem to increase the viscosity appreciably.
Chart No. 9 shows that the presence of 70 per cent. heated sheep serum
(55°C. for 24 hours) requires 2 . 4 times as much complement to be used for com
plete lysis as is required when it is replaced by 0.85 per cent. NaCl. The same
serum heated for 30′ o n l y i s s t i l l m o r e i n h i b i t o r y , s o t h e p r o l o n g e d h e a t i n g a p p e a r s
to destroy some of the inhibitory power. The 24 hours' serum was markedly more
viscous than the 30′ serum.
To estimate the effect of viscosity of the suspending medium, experiments
were made with inert substances which had no lytic action themselves. Concen-
trations of egg-albumin and gelatine were selected which had higher, equal and
lower viscosities than the heated sheep serum used. The tonicities of the three
groups, egg-albumin, gelatine and heated sheep serum were rendered as nearly
equal as possible, so no interference from this cause can be admitted.
The highly viscous 32 per cent. egg-albumin did not retard lysis, in fact the
series was almost the same as when only 0 . 85 per cent. salt was present whereas
the heated sheep serum did. Similarly in the case of 1.6 per cent. gelatine. So
the inhibition by heated sheep serum is not due to its viscosity.
TABLE NO. -15.
No .
Viscous medium.
Percentage in
mixture.
Concentration of
complement.
Lysis.
1
Egg-albumin
...
...
..,
...
5.0 per cent.
0.075
Complete.
2
Do.
...
...
...
...
...
17.0
„
0 . 0 7 5
„
3
...
..
Do.
...
...
...
32'0
„
0.15
,,
4
5
6
7
Gelatine...
0.85 per cent. NaCI. control
...
...
,.,
Gelatine ...
...
...
...
...
...
0.32
„
0.8
I,
1.6 per cent.
0 15
0.2
0 . 2
0.25
,,
S
Heated sheep serum
...
...
...
...
65.0
„
0.25
Partial.
Viscosities of
,,
,,
1 & 4
2 & 5
3 & 7
<viscosity
=
,,
>
,,
S
S
8
In column 4 the lowest concentration of complement which completely lysed 0 . 05 sensitized
RBCs is entered.