336 The Vital Phenomenon: Assimilation 
plasmic movements of expansion and contraction would 
correspond.?°* 
Now it is evident that this endeavor not to attribute 
to vital energy any specific nature of its own, and con- 
sequently to explain even the most characteristic phe- 
nomena of life by means of only those energies which 
physics and chemistry afford us to-day, can have no 
more success than as if one should attempt to explain 
chemical phenomena by means of physical phenomena 
only. For the conception that the form of energy on 
which vital phenomena are based is different from all 
forms of energy which have hitherto been observed in 
non-living bodies, has absolutely nothing unscientific in 
it, any more than the conception, for example, that electri- 
city may also be a form of energy different from all 
others. 
Vital energy, nervous energy, we admit at once, will 
certainly be a particular case of the more general physico- 
chemical forms of energy already known or yet to be 
known, and as such it must necessarily be subject to 
the laws which control these latter; and also, a fortiori, 
to the laws which control all energy in general. But even 
as such, that is as a particular case of more general, 
physico-chemical forms of energy, it will have besides 
further special laws of its own which are only experi- 
mentally to be determined and cannot be deduced from 
the more general laws even though it must always be 
subjected to them. And it is just these laws of its 
own which, out of a physico-chemical energy, make it 
vital energy. This conception has led us to attribute 
to nervous energy, set forth as the basis of life, special 
253Verworm: Die Biogenhypothese. Jena, Fischer, 1903; and 
Die Bewegung der lebendigen Substanz, especially P. 100—103. 
