QUARTERLY CHRONICLE OF MICROSCOPICAL 
SCIENCE. 
HISTOLOGY. 
Blood.— Professor Neumann, of Kénigsberg (‘ Archiv der 
Heilkunde,’ bd. x1, p. 187, 1871), continuing his researches 
on the formation of blood-corpuscles, noticed in our last num- 
ber, has observed coloured nucleated cells, which he regards 
as transitional forms between the white and red corpuscles 
of the blood, in several instances in the blood of new-born 
children (born at the full time), and concludes that the 
embryonal formation of blood must go on till a later period 
of*development than has been generally supposed—certainly 
beyond the fifth month indicated by Paget. Further re- 
searches must show how long these embryonic forms survive 
after birth ; they were found wanting in the case of a child 
who died at sixteen days (of disease). Kolliker had previously 
found them in the spleen and liver of new-born infants. 
Neumann has found the same embryonic type of blood-cell in 
the blood of two persons suffering from the disease known as 
* Leukeemia”’ (or in England, “ Leucocythemia”’) ;' a fact 
well worthy the attention of physicians. 
Medulla of Bones.—In the account which we lately gave 
of the researches of Neumann on the structure of the osseous 
medulla and its relation to the formation of blood, no men- 
tion was made of the parallel and independent researches of 
Bizzozero,” of Pavia. In ‘ Virchow’s Archiv’ (vol. li, p. 156, 
heft. 1) a summary of Bizzozero’s researches is given, to 
which we are indebted for the following abstract.2 He dis- 
1 The occurrence of coloured nucleated cells in the blood of mammalia has 
been observed in many isolated instances. Professor Rolleston has ob- 
served them in the blood of the two-toed sloth, and has given several re- 
ferences to similar observations (see ‘ Quarterly Journal,’ new series, vol. vii, 
p. 127, 1867), one of which, by Mr. Busk, in this ‘ Journal,’ 1852, refers to 
man. berth found the same in a case of leukemia (‘ Virch. Arch.,’ 
xliii, 8. 
2 «Sul Midollo delle Ossa,’ studi del Dr. G. Bizzozero. Napoli, 1869. 
3 Professor Virchow remarks, in a footnote, that he himself long ago 
