198 W. WALDEYER. 
budding, is especially frequent in pathological new formations, 
has already been repeatedly insisted upon by Virchow, e.g. 
1857, in ‘ Arch. fur path. Anatom,’ Bd. xi, p. 89, and especially 
in his article on stimulation and irritability (“ Reizung und 
Reizbarkeit ”), ibid., Bd. xiv, 1858, but this was undoubtedly 
without any knowledge of karyokinetic phenomena. Indirect and 
direct fragmentation are, according to J. Arnold, the forms of 
division most frequently met with in lymphoid cells, as well 
as in giant-cells. The giant-cells exhibit it both in the normal 
occurrence in marrow, as well as in their artificial culture after 
insertion of pieces of elder-pith into a lymphatic or into a 
serous body-cavity, as was done first (in connection with 
culture of giant-cells) by Bernhard Heidenhain (87) at my 
suggestion, and as has recently been carried out by Arnold in a 
very successful way. With regard to the giant-cells of marrow, 
Arnold’s views have received contradiction from Denys, Cornil 
(49), and Fitterer (74). Denys (54) was unable to recognise 
the so-called “indirect fragmentation” of Arnold, i.e. frag- 
mentation accompanied by mitotic phenomena. He finds 
either only a “ direct division ” (without either an increase or 
a change of chromatin) or a true mitosis (Arnold’s “ indirect 
segmentation ””) in which the nucleus, after the appearance of 
regular V-shaped chromatin loops, their longitudinal splitting, 
daughter-wreath, &c., divides into a large number of equal- 
sized daughter-nuclei, with corresponding segmentation of the 
cell. Denys was also unable to recognise the aberrant form 
described by Cornil. From the latter’s figures of “ direct divi- 
sion,” we are reminded of a process of budding (Sprossungs- 
Vorgang), and I do not see why we should not retain this very 
descriptive and familiar name. 
I have now to take up the question as to the rela- 
tion of direct to indirect nuclear division. Are there, 
in fact, two different modes of division which have no 
intermediate stage, or is there only one fundamental form of 
nuclear division, which, like nearly all complicated organic 
processes, varies greatly under different circumstances, so that all 
the different changes represent only links ina chain, which can 
