218    PREPARATION OF ANTI-RINDERPEST SERUM.

explain the absence of anti-toxin in the precipitates obtained
by Dieudonné and by Belfanti and Carbone. Fuld and Spiro
(1900), divided the globulins occurring in horse serum into three
classes—fibrinoglobulin, euglobulin and pseudoglobulin—the
classification being based upon the degree of saturation of am-
monium sulphate required to produce precipitation, and Pick
(1902) showed that the anti-toxin occurring in the serum of
immunised horses is associated or combined with the pseudo-
globulin fraction. Pick makes the interesting observation that
in the case of goats immunised against diphtheria toxin the anti-
toxin occurs in the euglobulin fraction, but Gibson and Collins
(1907), and Ledingham (1907), were unable to confirm this.
Ledingham found that during immunisation of a horse that
ultimately yielded a high grade anti-toxin, the percentage glo-
bulin content of the total protein progressively increased, and
the increase affected the euglobulin more than the pseudoglo-
bulin fraction. In a horse which yielded a low grade anti-toxin
no such increase of globulin was observed.

With regard to the distribution of other immune bodies in
immune serum less information is at hand. Tetanus anti-
toxin was not found in the precipitate obtained from immune
serum either by dialysis or by means of carbon-dioxide and
acetic acid, but occurs in the precipitate obtained by saturation
with magnesium sulphate (Tizzoni and Cattani, 1891). Ac-
cording to Pick tetanus anti-toxin, like diphtheria anti-toxin,
is combined or associated with the pseudoglobulin fraction of
the serum. The same author states that the typhoid agglutinin
of horse serum also occurs in the pseudoglobulin fraction, while
cholera lysin and cholera agglutinin in the horse and goat
occur in the euglobulin fraction. Gibson and Collins (1907).
found that the agglutinins for the dysentery group of organisms,
typhoid, colon and cholera were not confined to either of the
globulin fractions. Landsteiner (1908), showed that the sub-
stance occurring in normal serum which exerts an anti-tryptic
effect is associated with the albumin fraction of the serum,
and this was confirmed by Cathcart (1904). Opie and Barker