888 
of Spitzenburg are now better than the 
forest crab, from which they probably 
came. Perfection is therefore a relative 
term, in the same sense that disease is a 
relative term, and a just comparison 
can only be made with the average. That 
which is now considered perfection may 
be very imperfect in the future, and that 
which is now a standard of health may 
be considered stunted, because it may 
fall below the average 
Nature of the Organism and Disease 
There is much more knowledge than 
formerly upon the nature of organisms and 
their adaptations to particular localities. 
It is understood that no two things in na- 
ture are exactly alike; but several things, 
like apples, for instance, are sufficiently 
alike so that the conditions necessary for 
the growth of one variety may be favorable 
for the growth of another variety. Still, 
it remains true, that the different varie- 
ties of apples are in many particulars 
unlike, and that the unlikeness is suffi- 
ciently marked so that conditions favor- 
able for the growth of one variety may 
not be the best for another, and in some 
extreme cases are decidedly unfavorable. 
This is the reason why the American 
Pomological Society has divided the 
United States into districts and has giv- 
en a list of the various fruits and their 
varieties that are “Successful, very suc- 
cessful, fairly successful and recom- 
mended for trial,” in the different dis- 
tricts, (See page 192). 
We will compare a few plants that 
belong to different species, rather than 
those of the same species, as illustrating 
our idea. Take celery, cress and cran- 
berries as illustrations of plants that re- 
quire a great amount of water. In a dry 
soil, where the sun was hot, they would 
sicken and die. On the other hand, al- 
monds, sand-plums, sage brush and cacti 
would reach a normal condition and 
manifest health where the first named 
group would die. This is on account of 
the nature of the organism, which adapts 
one to a wet soil and the other to a dry 
soil. Because of this difference it would 
be folly to expect success in the growing 
of celery without plenty of water, or to 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
expect success with almonds in a damp 
or sub-irrigated soil. 
All Plants Once Aquatie 
It is taught by geologists that in the 
early history of our globe the whole sur- 
face of the earth was successively cov- 
ered with water, and that all vegetable 
and animal life was adapted to the wa- 
ter. With the changes that came from 
the shrinking of the surface of the earth, 
the consequent upheavals, the building 
of mountain ranges and the valleys be- 
tween them, the subsequent draining 
of great basins of lakes and seas, and 
the consequent forming of deserts it came 
about that gradually both plants and 
animals became adapted to the many con- 
ditions existing between the extremes of 
water and desert. The struggle of all 
forms of life is for existence and the 
tendency is in the direction of those 
changes necessary to existence and to 
adapt the organism to a given environ- 
ment. The plant that cannot become 
so adapted will in so far as that par- 
ticular locality is concerned, become 
extinct. Naturally, therefore, the plant or 
tree that is adapted to the desert will 
have a small leaf surface, from which 
little water can be evaporated, or if the 
leaf surface is large as in the case of the 
cacti, it must have few stomata, or 
pores, from which the water can be 
taken by the action of the heat. It must 
also have a root system, adapted to the 
dry soil conditions under which it lives. 
Another example of the leaf formation in 
adaptation to the different conditions is 
the difference between the Indian corn 
and the Kaffir corn. The latter having 
a thick, compact leaf with few cells ex- 
posed to the air and which admits of a 
small amount of evaporation, lives in 
dry regions. For this reason certain va- 
rieties of peaches will live and bear fruit 
where other varieties would die, and 
watermelons will grow successfully 
where pumpkins and muskmelons would 
fail. It has, therefore, come to be ob- 
served, that plants have certain likes and 
dislikes, growing out of the nature of the 
organism, and that if any particular plant 
gets what it likes it is healthy, but if it 
does not, it becomes diseased. 
