174: W. WALDEYER. 
distinguished from those of the spindle figure (van Beneden, 
fig. 11). Besides the longitudinal splitting of the threads, 
however, the final stage of the “skein” exhibits during its 
course a series of other remarkable phenomena, chiefly the 
appearance of the so-called ‘‘ achromatic nuclear spindle,” and 
the commencement of the arrangement of the chromatic loops 
in a different position with respect to this spindle. 
The well-developed nuclear spindle is shown in fig. 7; it 
consists of two poles and an equator. The delicate threads of 
which it consists are stained, as already mentioned, much more 
feebly than the thicker threads of the chromatic figure, at any 
rate with Flemming’s so-called true nuclear stains (alum-car- 
mine, anilin, Bismarck brown, gentian violet, methyl green, 
&e.), whereas on the other hand they become coloured by 
many carmine solutions, as well as by hematoxylin. The threads 
are much more delicate than those of the chromatic figure, 
especially in animal cells ; but in plant-cells the spindle figure 
becomes evident almost directly... According to Carnoy these 
threads are continued into the cell-protoplasm at the two 
poles (cf. van Beneden below, and fig. 7, ‘‘ Cytaster ”’). 
Further study of the achromatic threads shows that the 
spindle-threads disappear in solution of pepsin, and are ren- 
dered distinct in weak acids, especially hydrochloric. The 
figure has not always the shape of a spindle, but in plant-cells 
especially, it not infrequently presents a cylindrical shape 
(‘‘ cylindrical thread-bundle”), so that when seen from the 
pole it resembles not a star but a dotted barrel or tub. 
As to its origin and meaning opinions differ. I shall return 
later on to this subject. 
1 The most distinct spindle figure in animal cells, which I have had the 
opportunity of seeing, is in some very beautiful preparations by Mayzel; 
these are preparations of the epithelium of Descemet’s membrane of the 
Frog (Rana esculenta). They were treated with weak chromic acid, and 
stained with carmine, and remain well preserved in glycerine after some years, 
without losing their distinctness. (Cf. Mayzel’s work (184) in the ‘Fest- 
schrift zu Ehren Hoyer’s.’) Recently I studied the spindle in the most 
perfect form in Kultschitzky’s preparations of the eggs of Ascaris megalo- 
cephala made in this laboratory. 
