ses is mainly at work. In acute anaemias, such
as those associated with septicaemia, there is no doubt that blood
destruction plays the principal part. But if the cause of anaemia is a
chronic one, a gastric cancer, for instance, though there may possibly
be an increased amount of destruction of corpuscles in some cases, and
though there is often loss by haemorrhage, the cancer interferes with
nutrition, the blood is impoverished and does not nourish the
erythroblasts in the marrow sufficiently, and the new corpuscles which
are turned out are few and poor in haemoglobin. In chronic anaemias,
regeneration always goes on side by side with destruction, and it is
important to remember that the state of the blood in these conditions
gives the measure, not of the amount of destruction which is taking
place so much as of the amount of regeneration of which the organism is
capable. The evidence of destruction has often to be sought for in other
organs, or in secretions or excretions.

Of the so-called primary anaemias the most common is _chlorosis_, an
anaemia which occurs only in the female sex, between the ages of fifteen
and twenty-five as a rule. Its symptoms are those caused by a diminution
of haemoglobin, and though it is never directly fatal, and is extremely
amenable to treatment with iron preparations, its subjects very
frequently suffer from relapses at varying intervals after the first
attack. Its causation is probably complex. Bad hygienic conditions,
over-fatigue, want of proper food, especially of the iron-containing
proteids of meat, the strain put upon the blood and blood-forming organs
by the accession of puberty and the occurrence of menstruation, all
probably play a part in it. It has also been suggested that internal
secretions may be concerned in stimulating the bone-marrow, and that in
the female sex in particular the genital organs may act in this way.
Imperfect assumption of function by these organs at puberty, caused
perhaps by some of the above-mentioned conditions, might lead to
sluggishness in the bone-marrow, and to the supply to the blood of the
poorly-formed corpuscles deficient in haemoglobin which are
characteristic of the disease. Chlorosis is the type of anaemias from
imperfect blood-formation. Lorrain Smith has produced evidence to show
that the total amount of haemoglobin in the body is not diminished in
this disease, but that the blood-plasma is greatly increased in amount,
so that the haem