248 Theories Treating of Inheritance 
the organism upon another; so also the morphological 
changes in animal ontogeny arise in the same way 
through manifold inductive stimuli ‘“Inductionsreize” 
which are almost always of internal origin.” °° 
This conception, especially if it is extended to the 
whole process of development in general, would really 
amount to a reduction of ontogeny, exactly as in the plant 
formations above mentioned in which external agents act 
as true formative stimuli, almost to a phylogeny, con- 
stantly repeating itself anew in each generation. And 
the fact that successively arising generations would in 
spite of that remain always alike is to be attributed to the 
repetition, proceeding always in the same way, of succes- 
sive functional stimuli both without and within the 
organism in process of development, which are produced 
gradually one out of the other through the principle of 
fructifying causality and give rise each time to these new 
phylogeneses. 
In this respect the conception of Herbst recalls the 
purely mechanical explanation of development given by 
His, who refers the appearance of the same ontogenetic 
phenomena every time to the repetition of definite me- 
chanical influences, proceeding always in the same way. 
Since each influence, itself induced by the influences 
preceding it, induces in its turn the influences following 
it, then if only the first link of the chain is constantly 
repeated in the same way in each generation, that would 
be enough to cause the same thing to happen in the case 
of all the others. 
**8Herbst: Uber die Bedeutung der Reizphysiologie fiir die 
kausale Auffassung von Vorgangen in der tierischen Ontogenese. 
Biol. Centralbl. 1894. Bd. XIV. No, 18—22. P. 771; and Bd. XV, 
N. 20—24. P. 852. 
