OHIO SPATE ACADEMY OF SCIENCE. 25 
climatic conditions embracing differences in the amounts of 
heat, light and humidity, exposure to dryness in air or soil as 
well as the encroachments of animal life by the cropping of 
herbivors or the fretting of insects. In response to contin- 
uously acting stimuli of this character the plants become 
modified or adapted to the conditions surrounding them; 
the study of this adaption leads to Ecology. 
Studying still these same plants as living organisms, 
and either in their general functional activities or in their 
external and internal adaptations or in both, we find that 
the course of the life of the plant is by no means always 
normal — instead of simple turgor we may have tumes- 
cence or edema (dropsy as our physicians would say ) ; in- 
stead of the free water flow contemplated through the 
conducting tissues we may find the vessels closed. Not 
only this, external and internal parasites may attack any 
and all organs of the plants, intercepting light and heat, 
absorbing, destroying or diverting the usual nutritive sub- 
stances, penetrating and transforming essential organic tis- 
sues, and even totally preventing the attainment of the 
reproductive functions; these parasites may lie in wait in 
the soil, be wafted in the winds, or be sown with the seed 
of the husbandman. Otherwise incapable of striking ex- 
pression by external signs, the plant may find itself fixed in 
a soil with inadequate or unsuitable, or even injurious sub- 
stances contained therein; accordingly there is stunted 
growth, reduced vigor or manifest ill health indicated by 
fruit or foliage. Abnormalities are seen in such and in other 
ways; their study just as certainly leads us to Vegetable 
Pathology. 
Pathology is then, at least, tentatively ranked coordi- 
nately with Physiology and Ecology among the divisions 
of botanical science which have to do with plants in their 
- life relations. No one of these divisions just enumerated, 
more than another, may be successfully cultivated without 
some knowledge of the other divisions of botany and of 
allied sciences. 
