1885.] The Relations of Mind and Matter. 537 
the continued activity and supremacy of these forces. Yet all 
such compounds are constantly subject to the action of external 
forces, and are occasionally disintegrated or otherwise affected 
thereby. The more complex the compound the more exposed is 
it to the disturbing influence of external energy. At the same 
time the more complex the chemical compound, the less vigorous 
is the action of the innate energies of affinity. It is evident, 
therefore, that at some point a balance between these opposed 
energies must be reached. While chemical energies continue 
superior there must be a gradual increase in the complexity ot 
compounds, despite the assaults of external energy. But when 
these opposing energies become definitely equal in vigor, it seems 
evident that a fixed status must result. There may be upward 
and downward swings, as one or the other agency gains a tempo- 
rary supremacy, but the general level cannot permanently be 
departed from. 
Such is apparently the chemical status of protoplasm. It indi- 
cates the level of balance between internal and external energies. 
If it be broken down by a vigorous influx of external energy, 
the activity of chemical energy becomes superior, and reintegra- 
tion sets in until the balance of forces is again attained. Chem- 
ism cannot go further and produce a stable compound of higher 
complexity. Yet there is good reason to believe that unstable 
compounds of this high character are frequently produced, mole- 
cules lifted above the general level, and therefore liable to break 
= down instantly at the least influx of external energy. It is prob- 
ably to the existence of such excessively complex molecules that 
the high sensitiveness of nervous and muscular tissue is due. 
Lifted too far above the level of harmony of the forces, they break 
- down at a touch. 
Other results follow. Motor forces are set free within the tis- 
sue which give it self-motion. This self-motion brings it into new 
relations with external substances, and other changes than purely 
chemical ones follow. Variations in form and constitution in 
response to these external influences take place. Natural selec- 
tion upon function and form comes into play, and the organism 
that resists the adapting influence of external energy ceases to 
exist. Only those mobile organisms that readily yield to the 
molding influence of external energy, and closely adapt them- 
selves to the conditions of nature continue to exist. Thus in the 
