162 The Philippine Journal of Science i»« 



Years ago, my friend Professor Peirce ■ 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. 



'Proc. California Acad. Sci. Ill Bot. 1 (1899) 230. 



