Histology of the Blood, Normal and Pathological

erning the origin of the blood elements, we must shortly indicate

stages of the normal red blood corpuscles. Hayem's theory, on the contrary, obstinately asserts the origin of the e

lled secondary an?mias, and in leuk?mia, nucleated corpuscles of the normal size, "normoblasts"; in pernicious an?mia excessively large elements, "mega

a similar division of the nuclea

equivalent to the blood cells of reptiles and amphibia ("ancestor corpuscles"), and (2) of the usual size of the blood corpuscles of mammalia. And similarly more recent authors, H. F. Müller, C. S. Engel, Pappenheim and others, have adhered to the division of h?matoblasts into normo- and megaloblasts. And it is on

denies the principal distinction between them. Schaumann also holds that the separation of the two kinds rests on doub

eated red blood-corpuscles on the

cleus lies generally in the centre, comprises the greater part of the cell, and is above all distinguished by its intense colour with nuclear stains, which exceeds that of the nuclei of the leucocytes, and indeed of all known nuclei. This

ion to a greater or less degree. The nucleus is larger than that of the normoblasts, but does not form so considerable a fraction of the cell as in the latter. It is often not sharply defined, and is o

cribed, which are therefore called gigantoblasts, but which ar

loblast or a large normoblast. In such cases one would naturally search the preparation for perfect forms of h?matoblasts, and

g. in traumatic an?mias, but they are very seldom foun

st the distinction between these two cell forms. After surveying the literature, we are forced to separate the megaloblasts from the normoblasts

leaves the cell, which thereby becomes a complete erythrocyte, whilst the nucleus itself, by the aid of the small remnant of protoplasm which surrounds it, takes up new material from the surrounding plasma, manufactures h?moglobin and so becomes a fresh erythroblast. According to the seco

ss described, as it occurred in physiological saline solution with t

of the blood from the sodium chloride solution and the teasing. If a method of preparation be chosen which protects the blood as fa

and leuk?mic blood, the transition from erythroblast to erythrocyte is shewn by all phases of nuclear metamorphosis. v. Recklinghausen professes to have directly observed the dissolution of the nucleus within the cell in rabbit's bl

Rindfleisch and Neumann. He taught that both kinds take part in the production of the red discs. From blood preparations which contain numerous normoblasts, for instance in "blood crises" (see p. 62), an unbroken series of pictures can easily be put together shewing how the nucleus of the erythroblast leaves the cell, and at last produces the appearance of the so-called free nucleus. It must be expressly mentioned that these pictures are only to be found in specimens in whose preparation pressure of any kind upon the blood has been avoided. Further, however rich a blood may

normocytes by extrusion or emigration of the nucleus, the megaloblas

ch, also concludes from his researches on sections of the bone-marrow of an

rvation he chose the blood of embryonic mice. He was able in the first place, like Rindfleisch, to produce the exit of the nuclei from the cells by the addit

uclear destruction and solution within the cell, be it in the case of megalo

ing remnants of the degenerated dying blood cells. Clinical observation, certainly, does not support this conception of Pappenheim's; in as much as in suitable cases with numerous free nuclei (leuk?mia, blood crises) transitional forms, which accord

n content of the cells-although as we have described above, these are in general different in normo- and megaloblasts-for these two properties undergo such great variations as to increase considerably under certain circumstances the difficulty of diagnosis of individual cells. The chief characteristic is, as Ehrlich has always particularly insisted, the constitution of the nucleus. The nuclei of

disease of some kind. They are however mostly rather scanty, so that a preparation must be searched for some time before an example is found. B