The Panycncs. 643 
character on them, and this assumption furnishes an ex- 
planation of the fact that the functions of the cell-organs 
conform to the hereditary characters of the plants to 
which they belong. This migration from the nuclei is 
repeated at intervals, 1 and thus the body of the cell 
soon comes to consist almost solely of pangenes which 
have recently emerged from the nucleus. 
ii. THE PANGENES AS BEARERS OF THE HEREDITARY 
CHARACTERS. 
As an hypothesis, pangenesis serves a heuristic ob- 
ject; as a theory, it must serve as a basis from which a 
deeper insight into the nature of living substance may 
be obtained. I have not much to sav here as to its 
^ 
heuristic value, since for myself pangenesis has always 
been the starting-point of my inquiries ; at first only in 
a theoretical way, but afterwards also for the experi- 
mental investigations described in this book. 2 
Especially is it this hypothesis which has led me to 
search for mutations in the field, 3 because I hoped in this 
way to find facts which would throw a more immediate 
light on the bearers of hereditary characters, and thereby 
on the theory of heredity in general. 
The doctrine of pangenesis only touches the kernel 
of the general theory of heredity and leaves the details 
to special theories; but experience has taught me that 
1 My belief that the transportation of the pangenes is largeh 
brought about by the so-called streaming of the protoplasm and that 
this is a normal and general occurrence has not in the least been 
shaken by the arguments which have been urged against it. 
2 Se the bibliography at the beginning of this volume. 
3 1 should like to insert here the following little coincidence. 
My Intracellulare Pangenesis was written during the summer holi- 
days, spent near Hilversum in 1888, and the often described locality 
of Ocnot/icra Lamarckiana was only about ten minutes walk away. 
