39
TABLE NO. 18.
Animal.
Sheep S.
Sheep R.
Rabbit 101.
Relation of RBCs injected to weight
of animal.
1 / 1 9 2 0
1/320
1/160
Method of injection ...
...
...
7 cc once intravenously.
7 cc dail for 6 days sub-
cutaneously.
1 cc daily for 6 days
subcutaneously.
Time which elapsed before final injec-
tion.
18 days.
45 days.
45 days.
Relation of RBCs of test injection to
weight of animal.
1 / 7 9 0
1 / 3 5 0
1 / 1 6 0
Method of test injection
•••
•••
17 cc intravenously.
38 cc intravenously.
6 cc intravenously.
Result of test ...
...
...
...
Recovery.
Death 20 hours.
Death 1½ hours.
The above table shows the data of the experiment. The rabbit, whose
immunity was the highest and which received the largest proportionate doses of
washed sheep RBCs, was the first to succumb to the test injection ; Sheep R
succumbed after a longer period and sheep S, in which the presence of immune
body could only be demonstrated by means of additional complement, showed no
ill effects. The death of these animals was due to the condition. called anaphylaxis.
Anaphylaxis is an accident to an immunised animal which. can but rarely occur
under natural conditions and then only in a modified degree ; and the fact that an
animal, when in an immune state, is under certain conditions at the same time
highly susceptible to an anaphylactic accident in no way detracts from the value to
be placed on acquired immunity. It would appear that, in the case of animals
sensitized to foreign RBCs, there is a certain definite relation between the amount
of lysin present in the blood and the amount of the test inoculation which is
required to produce death.
Small quantities produce precisely the same influence as larger, but of lesser
degree; and the existence of this influence is demonstrated by the leucopenia and
proportionate reduction of the polymorphonuclears which occur. Andrewes
(loc. cit.) has shown that such leucopenia is due to the retention of the polymorpho-
nuclears in the capillaries of the lungs whither they are conceived to retire in order
to recuperate, whether to renew their stock of complement by oxygenation or for
other purposes is not known. That the blood is not the sole container of comple-
ment in the body is shown by Todd and White (Proc. Roy. Soc., Vol. 82, p. 418)
who injected a powerful isolytic serum intravenously into a bull. This serum had
no lytic action in vitro on the RBCs of the bull, unless foreign complement was
added, and yet the tissues of the bull somehow furnished complement in vivo, as
bæmoglobinuria followed.
The exact significance of death by anaphylaxis has not yet been decided. In
the case of the sheep immunised against goat RBCs a more harmless intravenous
injection than washed goat RBCs could scarcely be imagined, yet death. occurred
within 20 hours. Death can scarcely be dependent on the removal of the immune
body from the serum, for that is an artificial product, and, therefore, in no way
essential to the life of the animal. Nor it is likely to depend on the removal of
complement, whatever that may be, from the serum, for that substance, if Todd and
White's experiment is a criterion, can be supplied from the tissues. The solution
of foreign RBCs in the plasma cannot enter into the question, for such solution
may occur in the blood of a non-immune animal without harm to it. The degree
of leucopenia found is not greater than may be met with. in malaria for example.
The dyspnœic symptoms may have some mechanical basis such as plugging of
capillaries by leucocytes. In short, nothing so far known will account entirely
for the condition, even when Besredka's suggestion that it is due to changes in
certain cells of the central nervous system which are essential to life is included.