ORGANIC DEPENDENCE AND DISEASE 
35 
independence here indicated is essentially that of the Cam- 
brian fanna as a whole is an indication of how slowly sub- 
jection and dependence permeated the life of the earth. 
THE BEGINNINGS OF SYMBIOSIS AND 
PARASITISM 
In the foregoing we have endeavored to indicate that de- 
pendence is not a primitive but a secondary condition of 
organisms ; that, as the alternate state to independence, it 
had involved in lesser degree even so early a fauna as the 
Cambrian ; and in successive faunas to the present we have 
the full knowledge that it has vastly increased in its scope 
and effect. We have no reason to believe that the depend- 
ent habit of life once acquired has ever been fully removed 
or lost; it is safe to say that dependence, under the normal 
procedure of the organic law, is incurable ; an adaptation 
without escape. 
We are now to consider, not the expressions of race de- 
pendence, but those consociations among early animals 
which have led from conditions of mutual support and in- 
terdependence (symbiosis) into conditions of parasitism or 
absolute dependence of one animal or plant upon another’s 
vital functions. From the protozoa and bacteria to man 
and the oak, nature is riddled with such expressions of de- 
pendence and surrender. 
In the more innocent expressions of symbiosis termed 
mutualism and commensalism, where associations of or- 
ganisms are purely social and apparently harmless or even 
mutually advantageous to the participants, it is probable 
that once fixed the outcome is infalliblv deleterious. 
The glass-rope sponge (Hyalonema) has its coil of rope 
by which it anchors itself to the sea bottom, incrusted and 
shielded by a coral (Palythoa), which spreads like a thin 
wrap of felt all about it, while its ally the Venus’s Flower- 
