218 GERM-CELL CYCLE IN ANIMALS 
The elimination of chromatin during the matura- 
tion and early cleavage divisions of the egg, as well 
as during the mitotic divisions of other kinds of cells, 
has often been recorded. For example, Wilson 
(1895, p. 458) estimates that only about one-tenth 
of the chromatin in the germinal vesicle of the star- 
fish is retained to form the chromosomes during the 
first maturation division, and Conklin (1902) finds 
that ‘“‘in Crepidula the outflow of nuclear material 
occurs at each and every mitosis” (p. 51). Further- 
more, Rhode (1911) argues that chromatin-diminu- 
tion is a normal histological process, and describes 
such phenomena in blood cells, nerve cells, and 
cleavage cells of several AMPHIBIA, comparing con- 
ditions with the chromatin-diminution in Ascaris 
and Dysticus.+ 
Diminution processes similar to those in Ascaris 
and Miastor have not been discovered in other ani- 
mals, although investigators have been on the watch 
for such phenomena and have studied allied species, 
e.g., the work of Hasper (1911) on Chironomus and 
my own work on the chrysomelid beetles (see pp. 108 
1His conclusion is as follows: ‘In der Histogenese der allerver- 
schiedensten Gewebe tritt uns also die Erscheinung entgegen, dass 
die sich entwickelnden Zellen, bzw. Kerne einen Teil ihres Chromatins 
abstossen, d. h. also eine Chromatindiminution erfolgt, wenn auch 
die Befunde selbst im speziellen von den bisher beobachteten in der 
Einleitung beschriebenen Fallen der Chromatindiminution etwas ab- 
weichen. 
“Eine Chromatindiminution tritt also nicht nur am Anfang und Ende 
der Keimbahn, wie es bisher angegeben worden ist, sondern in den ver- 
schiedensten Entwicklungsstadien und bei den verschiedensten Geweben 
und Tieren ein, sie hat also offenbar eine allgemeine Bedeutung.” (p. 25.) 
