102 The Philippine Journal of Science 1916 
Years ago, my friend Professor Peirce 6 undertook to argue 
that the algal constituent of a lichen gained nothing from the 
association with the fungus, even though it was enabled to live 
in places, that without this association would be inaccessable 
or intolerable. To make his point perfectly clear, Professor 
Peirce makes use of “A homely analogy. A cow would never 
climb to the top of a twenty-story building, but once elevated 
to this position in opposition to her ordinary habits and to the 
force of gravitation, would she be any more advantageously 
placed than her more commonplace relatives in barn or pasture?” 
A Chinese student in this college once presented, as a piece of 
English composition, the story of an imaginary dream, in which 
he saw the vacant places of the earth occupied from time to 
time and made productive for the use of men, until every desert 
was watered and every rock covered with a mantle of soil. 
The mountains were leveled to an altitude where rice could be 
produced; and finally even the seas were bridged, and the 
bridges covered with soil and made to produce their crops of 
rice. 
The Chinese boy’s imaginary dream is truer to life than the 
argument of the wisest professor who overlooks the fact that 
the one test of fitness, of appropriateness, is survival. As the 
struggle for food grows keener, the time may indeed be 
anticipated, when no foot of the Earth’s surface can well be 
spared from producing its portion for our use. That time has 
not yet come for us; but for the lichen, for the Rubiaceae, and 
for the cow, it is here, and it has been here so long that we can 
almost say that it always was. The twenty-story building is 
located where there is no room for cattle in green pastures ; and 
where there are green pastures, there are already as many 
cattle as men think can thrive upon them. If the roofs of 
twenty-story buildings could really be made available as places 
for cattle, then more cattle might exist in each generation ; and 
this, by the one final standard of judgment, would be an advantage 
to the race of cattle and would assuredly be of advantage to the 
individual cattle that lived because this peculiar habitat fur- 
nished them the opportunity. The algal constituent of lichens 
grows in places that are fit for it and within reach. If slavery 
to a fungus increases the number that can live, by furnishing a 
new place or a means to reach a new habitat, this is to the 
advantage of the gonidial species, as well as that of the indi- 
viduals which live because of the opportunity the fungus offers. 
r ' Proc. California Acad. Sci. Ill Bot. 1 (1899) 230. 
