Mathematical Models for Blood Coagulation - Fluid-Structure Interaction and Biomedical Applications - page 481

Attention towards blood composition in the interpretation of the coagulation
process was brought by WilliamHewson (1739-1774), who isolated a “coagulation
lymph” responsible for the process (identifiable with what is known today as
fibrinogen ).
In the first part of the nineteenth century it became clear that limb swelling
had to be attributed to veins obstruction, though the struggle against the humoral
theory was still going on! 10 One of the most revered physician of the nineteenth
century was Rudolph Virchow (1821-1902), today still remembered in the field of
blood coagulation for his Virchow Triad , emphasizing three elements contributing
to thrombosis. In the modern language we can list them as hypercoagulability,
alterations of hemodynamics (stasis), and endothelial injuries. 11 He introduced the
term embolia . Of course there were many other physicians who had similar views,
but since this is not a historical paper it is more urgent to deal with the discovery of
platelets .
However, before we come to that, let us briefly mention some historical remark
about bleeding disorders. It is natural that such phenomena have been important to
people practicing circumcision. 12 Babies whose blood could not coagulate properly
could bleed to death. In the second century AD Rabbi Judah haNasi exempted
babies from circumcision when two sons of the same mother had previously died
after the operation (Babylonian Talmud). The Islamic physician Albucasis ( Abual-
Qasim Khalaf ibn al-Abbas Al-Zahrawi , 936-1013, dates are uncertain) who lived
in Andalusia, reported cases of what today is known to be hereditary hemophilia.
Accounts of bleeding disorders of hereditary type can be found in many later sources
and with different names. The term hemophilia was used for the first time by
Friedrich Hopff in his 1828 treatise Über die haemophilie oder die erbliche Anlage
zu todlichen Blutungen (Zurich). We know today that some classes of disorders
known as hemophilia (namely hemophilia A and B) are due to a defective gene in
the X-chromosome. That explains why it is extremely rare in women (possessing
two X-chromosomes), 13 who can however carry the illness (only one chromosome
being defective) without symptoms and transmit it through their genealogic tree.
10 It is really amazing that a well-known scientist like the Swedish Robin Fåhraeus (1888-1968),
still quoted today, for instance, in the field of blood rheology, believed to have found a confirmation
of Galens theories on the basis of the observation that blood coagulates in four layers with different
colours, corresponding to the famous humors [ 121 ].
11 Virchow described the mechanism of thromboembolism [ 240 ], a phenomenon that was by no
means clear at his time (inflammation was considered by many physicians the real cause of
thrombosis: this was the subject of a famous dispute with the French pathologist Jean Cruveilhier).
Curiously, he did not formulate the famous triad which for some reason found a firm place in the
literature much after his death (apparently not before 1950!). See the interesting review [ 17 ].
12 Circumcision is a very old practice, already found in the ancient Egypt and that was widely
adopted also in the Islamic world. Its origin in ancient Egypt was probably as an initiation practice
to religious offices. The Book of the Dead describes self-circumcision by the sun-god Ra: Blood
fell from the phallas of Ra after he had finished cutting himself .
13 In numbers, 1 over 10,000 men is hemophilic. The probability that a woman is hemophilic is the
square of that number.