126 
APPENDIX. 
Now we come to Weismannism proper : — Weismann sup- 
poses that these extremely minute rods, loops, or threads about 
A. — Cell with nucleus — n, 2 nd centrosomes 
— cs , preparatory to division. '1 he chromatin 
has become thickened so as to form a spiral 
thread — chr. 
B. — The nuclear membrane has disappeared. 
Delicate threads radiate from the centrosomes, 
and form the ‘ nuclear spindle,’ in the equator 
of which eight chromosomes or nuclear loops 
{chr) are arranged : these have been formed by 
the spiral thread of chromatin in A becoming 
broken up. 
C. — The chromosomes have each become 
split longitudinally into two, and are about to 
be drawn apart by means of the spindle-threads. 
(For the sake of clearness only four of the eight 
chromosomes are indicated. 
D. — The daughter-loops pass towards the 
poles of the spindle. 
E. — The body of the cell has undergone divi- 
sion ; each of the resultant cells contains a 
centrosome and eight nuclear loops. 
the distribution of which nature takes so much trouble, consist of 
masses of the hereditary substance, to which he gives the name 
