CHAPTER XII 
ANIMALS AND PLANTS 
ANIMALS, being incapable of manufacturing organic 
food themselves, are necessarily dependent, directly or 
indirectly, upon plants for their supply of food; but, 
on the other hand, many plants depend, more or less 
completely, upon animals for their existence. While 
these are usually flowering plants, still among the lower 
forms of plant life many instances might be cited, 
especially among the parasitic fungi, like the insect- 
fungi, and some water-moulds. The same may be said 
of many of the pathogenic bacteria, or disease germs. 
Occasionally insects appear to be useful to certain 
fungi by scattering their spores. Such fungi offer 
certain means of attracting insects, either in the form 
of a honey-like secretion, or their odor. Thus the 
evil odor given off by some fungi, especially the Phal- 
loidez, attracts carrion-loving insects, which carry away 
with them the spores which are imbedded in a slimy 
substance exuded by the fungus. 
It is among the seed-plants, however, that we meet 
with the most obvious adaptations connected with animal 
organisms. ‘The development of edible seeds and fruits 
in so many plants is, in most cases, directly referable to 
suchadaptation. Where the seeds themselves are edible, 
of course a large proportion are destroyed by the ani- 
242 
