NOTES AND MEMORANDA. 
The Origin of the Red Corpuscles of Mammalian blood. — 
A step forward in our knowledge of this subject has been made 
by Professor Einddeisch, of Wurzburg. As he justly remarks 
Archiv. f. mikrosk. Anatomie/ vol. xvii, August, 1879), in 
the introduction to his memoir, not a word is needed as to the 
usefulness, in fact the necessity, of continually renewed re- 
searches as to the site of the formation of the blood and its mode 
of formation. Who among us does not feel it as a wound, a 
painful raw in his scientific manhood that we still are unable to 
say ' Here and thus do the red blood-corpuscles take their 
origin Neumann and Bizzozero deserve the amplest recog- 
nition for their discovery that in the red marrow of bones, cells 
occur with reddish-yellow homogeneous protoplasm and well- 
marked nucleus, cells which accordingly are identical with the 
red blood-corpuscles of the earliest period of life. These obser- 
vations are easy to repeat and are fully accepted by all histolo- 
gists. From these observations we know clearly where besides 
in the spleen, we have to look for the great factory of the red 
blood-corpuscles. 
Haematogenesis is either a temporary or permanent function 
of certain regions of the connective-substance apparatus of the 
body, which for this purpose and during this period enters into 
an open communication wfith the lumen of blood-vessels either 
by the loss of their proper walls on the part of the capillaries 
and veins, as happens in the bone-marrow or by the thinning of 
their walls to such a degree, as in the spleen, that the unrestricted 
in-and-out wandering of cells becomes possible. The haemato- 
genous connective-tissue becomes a sort of accessory cavity for 
the lumen of the blood-vascular system. In this cavity haemo- 
globin-containing cells are produced by the conversion of 
colourless cells. Professor Eindfieisch compares the process of 
formation of haemoglobin in these cells to that of fat in fat- 
forming connective-tissue. 
Professor Eindfleisch^s special contribution to this subject 
consists in : 1st, a description of the vascular plexus of the 
marrow of mammalian bones which he has succeeded in injecting 
(using the rib of a young guinea-pig) and of the w^all-less 
character of its smaller vessels. 2nd, and of greatest import- 
