, or in volume,
the specific gravity would be correspondingly lowered. We should
therefore expect a low specific gravity in all anaemic conditions.
Similarly with an increased number of corpuscles, and a high haemoglobin
equivalent, an increase in the density of the total blood makes its
appearance.

Hammerschlag has found in a large number of experiments that the
relation between the specific gravity and the amount of haemoglobin is
much closer than between the specific gravity and the number of
corpuscles. The former in fact is so constant that it may be represented
by a table.

Sp. gravity Quantity of Haemoglobin
(Fleischl's method)

1033-1035 25-30%
1035-1038 30-35%
1038-1040 35-40%
1040-1045 40-45%
1045-1048 45-55%
1048-1050 55-65%
1050-1053 65-70%
1053-1055 70-75%
1055-1057 75-85%
1057-1060 85-95%

In a paper which has quite recently appeared Diabella has investigated
these relations very thoroughly, and his results partly correct, and
partly confirm those of Hammerschlag. Diabella found from his
comparative estimations that differences of 10% haemoglobin (Fleischl)
correspond in general to differences of 4.46 per thousand in the
specific gravity (Hammerschlag's method). Nevertheless with the same
amount of haemoglobin, differences up to 13.5 per thousand are to be
observed; and these departures are greater the richer the blood in
haemoglobin. Regular differences exist between men and women; the latter
have, with the same amount of haemoglobin, a specific gravity lower by 2
to 2.5.

Should the parallelism between the number of red blood corpuscles and
the amount of haemoglobin be considerably disturbed, the influence of the
stroma of the red discs on the specific gravity of the blood will then
be recognisable. Diabella calculates, that with the same amount of
haemoglobin in two blood testings, the stroma may effect differences of
3-5 per thousand in the specific gravity.

Hence the estimation of the specific gravity is often sufficient for the
determination of the relative amount of haemoglobin of a blood. It is
only in cases of nephritis and in circulatory disturbances, and in
leukaemia, that the relations between specific gravity and quantity of
haemoglobin are too much masked by other inf