To influences, of this moderate degree, belongs without doubt the anæmic constitution of the blood as such, the effect of which in this direction one can best investigate in cases of posthæmorrhagic anæmia.
In all anæmic conditions we observe characteristic changes in the blood discs.
A. =Anæmic or polychromatophil degeneration.=
This change in the red blood corpuscles, first described by Ehrlich, to which the second name was given later by Gabritschewski, is =only recognisable in stained preparations=. The red blood discs, which under normal circumstances stain in pure hæmoglobin colour, now take on a mixed colour. For instance, the red corpuscles are pure red in preparations of normal blood, stained with hæmatoxylin-eosine mixture. But in preparations of blood of a chromic anæmia stained with the same solution, in which possibly all stages of the degeneration in question are present, one sees red discs with a faint inclination to violet; others which are bluish red; and at the end of the series, forms stained a fairly intense blue, in which scarcely a trace of red can be seen, and which by their peculiar notched periphery are evidently to be regarded as dying elements.
Ehrlich put forward the theory, that this remarkable behaviour towards dyes indicates a gradual death of the red blood corpuscles, that is of the old forms, leading to a coagulation necrosis of the discoplasm. The latter takes up, as is the case in coagulation necrosis, the proteids of the blood, and acquires thereby the power of combining with nuclear stains. At the same time the discoplasm loses its power of retaining the hæmoglobin, and gives it up to the blood plasma in ever increasing quantity as the change proceeds. Hence the disc continues to lose the capacity for the specific hæmoglobin stain.
Objection has been raised to these views from many quarters, especially from Gabritschewski, and afterwards from Askanazy, Dunin and others. The polychromatophil discs are not, they say, dying forms, but on the contrary represent young individuals. The circumstance, that in certain anæmias the early stages of the nucleated red corpuscles are variously polychromatic, was evidence for this opinion.
In view of the great theoretical importance which attaches to this subject, the grounds for regarding this change as degenerative, may be here shortly brought forward.
