Febbuaey 26, 1915] 



SCIENCE 



307 



found. Variations and multiplications in 

 functions instituted by these associations, 

 with the resulting products, must influence 

 in the course of time the actual nature of 

 the organism. Its morphology, culture and 

 physiology must assume new aspects, for 

 this accords, by analogy, with recognized 

 laws of environment. If the highly devel- 

 oped molecular, protoplasmic complex is 

 sensitized, some fractional group or radical 

 thereof must yield its claim to some other 

 of siiperior affinity, which in turn will 

 manifest its presence in all probability 

 either morphologically, culturally or func- 

 tionally. 



Therefore, to suggest merely the richness 

 of a human sociology, a sociology of plants 

 and of animals, and a sociology of micro- 

 organisms in a parallelism, fits the mind 

 for the reception of the general principles 

 involved and their projections into the 

 larger field. It prepares the listener to 

 read in fullness between the lines uni- 

 written developments and unwritten bio- 

 logical laws expressed and observed in all 

 living forms. 



Humanists rightly call the social treat- 

 ment sociology, but were we to mention 

 plant and animal sociology and microbial 

 sociology, too much may be injected for 

 human euphony and it may be misleading. 

 For our purposes, microbial associations 

 are sufficiently inclusive and represent 

 many conditions of living together. This 

 is done advisedly, notwithstanding the 

 common usage of the term "symbiosis," 

 which, according to Minchin, should be 

 applied in a restricted sense to mutual 

 advantages on the part of each symbiont 

 involved. Difficulties are therefore avoided 

 by circumvention. 



In Frank's treatment^ of the biological 

 relationships his attitude is clearly revealed 



2 A. B. Frank, Beit. z. Biol. d. Pflans., Bd. 2, 

 S. 123, 1879. 



by his approach and classification. His 

 parasite depends upon another for nutri- 

 tion, but the other relationships as the ivy 

 and tree, and the mite and its hosts, as well 

 as De Bary's^ fungus and alga in myee- 

 tozoa, indicate only some of the more ap- 

 parent biological associations. They record 

 observations without knowledge and demon- 

 stration, without research and logical de- 

 ductions. They are of the order which 

 ■ rank among pioneer scientific effort. Like 

 superficial surveys, they were simply seen 

 and recorded and have been the means of 

 making it possible for a historical, consecu- 

 tive development. Frank admitted a classi- 

 fication, but, laboring as he did in ignorance 

 of the many facts which have come to light 

 since his time, his classification seems im- 

 pertinent. Others even later than this, as 

 De Bary, Hansen, Wortmann and Berlise, 

 would have included insects in the carrying 

 of pollen from fiower to flower, or yeasts in 

 the starting of fermentation changes, as 

 types of distinctive association. 



Probably the first tangible knowledge of 

 microbial associations may be traced to 

 Pasteur. It may be that this "Parent of 

 Microbiology" was not fully conscious of 

 the significance of associations, although 

 his work with anaerobic organisms, acetic 

 organisms and brewing organisms must 

 have conveyed an impression which made 

 his mind receptive to other possibilities. 

 There was an inference apparent in nearly 

 all the early work — that some single species 

 was wholly responsible for every recognized 

 process of fermentation or disease. The 

 emphasis thus given to pure cultures has 

 doubtless been the means of minimizing the 

 force and importance of mixed cultures; 

 for has it not been a common experience of 

 workers to witness persistent efforts in 

 securing results by means of pure cultures 



3 De Bary, "Comp. Morp. and Biol, of Myceto- 

 zoa and Bacteria. ' ' 



