2
(3) The nature of the immunity produced by anti-rabic inoculation.
We have made an attempt in the following pages to state facts, new and
old, which may tend to some extent to simplify opinions on these points. We
believe that a great many of the divergencies manifested in the different schemes
of different Institutes would be annulled if in each case the total quantity of
virus given within a certain period of time were looked upon as the ultimate
standard to which all treatment formulæ had to conform. At all events statistics
show that the success obtained in treatment by any one Institute does not differ
greatly from that obtained by any other, however diverse in appearance the
schemes employed. From this fact alone we would infer that the particular
scheme employed in any one particular place is not so important as the total
quantity of fixed rabies virus which is administered in a given time. Now,
whether we agree or not with the view 1 & 2 that slow drying of rabies material
simply results in diminution of the quantity of living virus contained in it, it
is still unquestionably the case that smaller quantities of less altered rabies virus
are the equivalent of larger quantities of more altered virus, however the alter-
ation (desiccation, heat, glycerine, etc.) may have been brought about. We shall
enter into this question later in all its bearings upon anti-rabic immunisation. As
a result of the fact just stated it may be asserted that ample opportunity is
afforded—and verily it has been made full use of—to construct a variety of
schemes of treatment according to individual idiosyncrasy without involving any
final difference in the dose administered to the patient. An illustration will make
our meaning clear. A cord which has been drying for five days is still infective
though not so infective as a cord which has been drying for only three days.
Quantitatively expressed this might conceivably be equivalent to saying that
1 grm. of three-day cord was equal in strength to 2 grms. of the same cord
after five days drying, or that a given quantity of three-day cord will produce
exactly the same effect, other things being equal, as twice the quantity of five-day
cord. We can then understand how it may come about that in one Institute a
certain quantity of three-day cord might be administered to a patient whilst in
another Institute, in the same circumstances, twice the amount of five-day cord
might be given and with equal effect. This simple fact we think goes far to
explain many of the divergencies in different schemes of treatment. These
divergencies might be reduced to conformity if we were able to give definite
values in units to definite quantities of rabies cord dried* for definite lengths of
time or to definite dilutions of fresh rabies virus.
1 Pasteur, Lettre sur la Rage ; Ann. de l' Inst. Past., 1887.
2 Höyges' Art. 'Lyssa' in Nothnagel's " Specielle Pathologie and Therapie," pp. 148, 161.
* We use the term ' dried ' for convenience to express the idea of alteration in rabies virus, however it
is brought about, instead of repeating on each occasion the various processes, such as desiccation, heating,
use of glycerine, etc., by which that alteration is effected.