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53
fever cases was by no means evenly distributed throughout the department, some
class rooms free from scarlet fever having had almost as many cases of sore throat
as the class room with most scarlet fever cases. In this room a selection was made
of children who had recently been absent for sore throat, as well as of those showing
enlarged tonsils or marked redness of the fauces. Throat swabbings were planted
on serum and subcultured on blood agar from eleven of the selected children, and from
eight of them or 72 per cent, a hsemolytic streptococcus was isolated. To four of
the strains a limited number of fermentation tests were applied and showed that
in each case mannite was not fermented.
Although the proportion of cases among the selected children yielding a hæmolytic
streptococcus was relatively high and therefore suggestive, the scope of this
single investigation was obviously too limited to admit of any real conclusions,
and notably in the absence of the necessary serological tests, in addition to control
culture tests as applied to children in other class rooms free from scarlet fever but
affected by sore throats, as well as in rooms free from both.
As already stated hæmolytic streptococci have been recognised as normally
present in the throats of about 10 per cent. of ordinary individuals. Their significance
as indicative of risk of transferring infection whether in the form of scarlet
fever, puerperal fever, or (very doubtfully), in a few instances of some non-specific
cases of pemphigus, is as yet far from being understood.
If there is any correlation existing between the incidence of scarlet fever, prevalence
of sore throat and the carrier state in the normal throat, it is perhaps not
unreasonable to surmise a possible relationship between the strains of hæmolytic
streptococci occurring in the three conditions respectively; which further suggests
the interaction of the " seed " and the " soil " in the extent of immunity response
evoked by the one from the other; in the insusceptible individual productive of
a harmless saprophytic state, in another, more susceptible, of a strictly local lesion
e.g., tonsilitis or pharyngitis, and, in the non-immune, of true scarlet fever. The
degree of immunity may, however, not be the only factor governing the issue ; but
a more decisive unknown third factor or virus, in addition to the known streptococcal
seed and susceptible soil, may be required to play the determining part in producing
an attack of scarlet fever.
In a recent paper by O'Brien and Okell (Public Health, May 1926, p. 246) on
the Dick Test, the existence of many points requiring explanation and further
study is emphasised, such, for instance, as to whether all scarlet fever toxaemias are
due to the same toxin, whether there are different toxins in true scarlet fever, or,
in other words, immunologically different types of the disease. They also refer to
the suggestions, made by Rundle, that there are two or more types of scarlet fever,
and by Park as to a possible wide antigenic (i.e., anti-body producing) overlap
between the different streptococci, e.g., ordinary scarlet fever toxin containing
antigenic or toxin components a, b, c, d, and others containing a, b, c, e and so forth.
Certain observations lately made by Dr. G. H. Eagles at the Lister Institute are
suggestive of the existence of some common affinity, in that the toxins derived from
hsemolytic streptococci, e.g., those obtained from scarlatinal throats, convalescents,
puerperal fever, erysipelas and pyogenes infections may, when injected intracutaneously,
produce positive " Dick " tests. Similar positive results were obtained
by Sir Frederick Andrewes with the filtrate of a hsemolytic streptococcus from
lymphangitis of the arm, when inoculated into a known positive Dick reactor, and
negative results when applied to a known negative reactor.
Moreover Eagles found that separate sera, obtained as the result of animal
inoculation with scarlatinal, erysipelas, and puerperal fever hsemolytic streptococci,
neutralised not only their corresponding toxins, but, severally, scarlatinal serum
neutralised erysipelas toxin, and vice versa, erysipelas serum, scarlatinal toxin;
and that in 40 to 50 per cent. of cases of puerperal fever the streptococcal toxin