vere anaemia should never be considered
closed, before three or four preparations at least have been minutely
searched for megaloblasts under an oil immersion objective.

This clinical difference between the two kinds of haematoblasts admits of
but one natural conclusion, which primarily leaves untouched the
question, so much discussed at the present time, whether the megalo- or
normoblasts can change one to the other. In all cases of anaemia, in
which the fresh formation occurs according to the normal type, only in
greater quantity and more energetically, we find normoblasts. Almost all
anaemias resulting from known causes: acute haemorrhages, chronic
haemorrhages, poverty of blood from inanition, cachexias, blood poisons,
haemaglobinaemia and so forth,--in short all conditions rightly called,
secondary, symptomatic anaemias,--may shew this increase of normal blood
production. In the conditions, which Biermer, on the grounds of their
clinical peculiarities, has distinguished as "essential, pernicious
anaemia" megaloblasts on the contrary occur, and represent an embryonic
type of development. The extent to which this type participates in the
blood formation in pernicious anaemia is most simply demonstrated by the
fact that megaloblasts are present in all cases of pernicious anaemia, as
Laache first shewed, and in some cases form the preponderating portion
of the blood discs. Whilst, therefore, in the ordinary kinds of anaemia
we find that the red corpuscles tend to produce small forms, in
pernicious anaemia, on the other hand, and exclusively in this form, we
find a tendency in the opposite direction. This constant difference
cannot be a chance result, but must depend on some constant law: in
pernicious anaemia excessively large blood corpuscles are produced.
Ehrlich's demonstration of megaloblasts has sufficed for this logical
advance. =All researches, which try to obscure or totally deny the
distinction between megaloblasts and normoblasts are wrecked by the
simple clinical fact that in pernicious anaemia the blood is
megaloblastic.=

The appearance of megaloblasts and megalocytes is therefore evidence
that the regeneration of the blood in the bone-marrow is not proceeding
in the normal manner, but in a way which approximates to the embryonic
type. The extreme cases are naturally seldom, such as that of
Rindfleisch, in which the whole bone-marrow was found full of
megaloblasts. It is sufficiently conclusive for the p