number of platelets it contains.

Marked =increase of the blood platelets= occurs in chlorosis (Muir) and in
posthaemorrhagic anaemia (Hayem). In both conditions there is a decided
=increase in the clotting power of the blood=. In contrast, is the
important observation of Denys, who found in two cases of purpura, where
as is well-known the =clotting power of the blood is always much lowered=
or may even be entirely destroyed, only one morphological blood change,
a very marked =diminution of the blood platelets=. Ehrlich likewise had
occasion to examine a similar case, in which the blood platelets were
entirely absent.

* * * * *

H. F. Mueller has described a fourth formed constituent of the blood, and
given it the name of "=haemoconiae=" or "=blood atoms=," "blood dust." It is
found in the plasma of the blood as very small granule- or coccae-like
colourless corpuscles, highly refractile, with a very active molecular
movement, which keep their shape under observation for a very long time
without any special precautions. According to Mueller these bodies are
not blackened by osmic acid, and probably contain no fat; they seem to
have no connection with fibrin formation, as they always lie outside
the fibrin network. Mueller found them in every normal blood, in varying
numbers however; much increased in a case of Morbus Addisonii;
diminished in hunger and cachexias.

More detailed observations are necessary to determine the chemical
nature of these forms. Experiments in this direction by extraction with
ether, or by the use of fat staining substances, alkanna, Soudan dye,
and comparative investigations on lipaemic blood should be successful.

FOOTNOTES:

[36] The physiological figures found by Brodie and Russell with the aid
of this method exceed considerably those of earlier authors. They found
a proportion of platelets to erythrocytes of 1:85 or an absolute number
of about 635,000 per mm.{^3}

LITERATURE[37].

~Altmann.~ Ueber die Elementarorganismen und ihre Beziehungen zu den
Zellen. _Leipzig_, 1 Aufl. 1890. 2 Aufl. 1894.

~Arnold.~ Zur Morphologie und Biologie des Knochenmarks. _Virchow's
Archiv_, Bd. 140.

---- Ueber die Herkunft der Blutplaettchen. _Centralbl. f. allg.
Pathologie und path. Anat._ Bd. 8, 1897.

~Askanazy.~ Ueber einen interessanten Blutbefund bei rapid letal
verlaufender Anaemie. _Zeitschr. f. klin. Med._ 1893, Bd. 23.

---- Ueber Bothriocephalus-