48 
the very scanty or almost deficient lymphatics of bone being 
equally so. 
An unprejudiced consideration of all these circumstances 
must lead to the conclusion, that though the theory of 
Neumann is hardly susceptible of direct proof, it has, at all 
events, a great deal to say for itself; and that the marrow 
deserves, if any tissue of the body does, special notice with 
respect to the question of the transformation of blood-cells. 
Eales’s own researches have been especially directed to 
the ribs, but he has obtained similar results from the 
apophyses of the long bones, the sternum, and the diploe 
of the skull. ' 
The method of investigation, which is substantially that of 
Neumann, is as follows: —A sawn-off piece of bone is 
gently pressed between a vice or pair of pincers till a thick 
reddish fluid oozes out from the cut surface. This is removed 
with a pipette and examined under the microscope without 
any addition, and is most advantageously covered with small 
fragments of covering glass. An enormous abundance of 
lymphoid cells, of the most various size, at once strikes the 
eye; true red corpuscles are present, but in very small 
number. The peculiar cell forms, designated as transitional, 
which are here soimportant, have been repeatedly observed to 
occurin varieties which may be arranged in the series described 
below ; a series forming a perfect chain of connection without 
any important break from the white to the red cells; or at 
least hardly admitting of any other equally satisfactory 
interpretation. Beginning with the white or lymph-cell the 
series is as follows :-— 
1. Colourless granular cells without a visible nucleus 
(ordinary lymph-corpuscles.) 
2. Smaller cells of the same kind, without more irregular 
outline, and without a visible nucleus. 
3. Cells almost of the same size, with a large granulated 
nucleus; and in its neighbourhood a few scattered granules ; 
and also with an annular or crescentic slightly yellowish 
border. 
4. Cells of the same size, with a similar border, a some- 
what smaller nucleus; no granules. 
5. Cells of about the same size, with a sharp outline, a 
somewhat more distinct yellow colour, and a still smaller 
granulated nucleus in the middle (halfway or middle stage.) 
6. The same with a more or less homogeneous, sometimes 
slightly concave nucleus. 
7. The same, with scattered irregular granules (remains 
of the nucleus). 
