I909-] GOODALE— DARWIN AND THE NATURAL SCIENCES. xvii 



nomenclature and in description. They placed Linnseus in the posi- 

 tion of a master whose word was law. Besides these two reforms 

 which were promptly and gratefully accepted, there was also a sug- 

 gestion made by him in regard to the identification of plants which 

 was so useful and attractive that it greatly increased his influence. 

 This suggestion led a host of amateur and professional explorers to 

 seek new plants in all countries. Your own city shared in this, as 

 Bartram's garden proves. Some of these plants were named and 

 described by the explorers themselves under the rules of Linnaeus, 

 but a large proportion of the remainder were placed at the disposal 

 of the great master. This convenient system of identification par- 

 took of the nature of a system of classification, thoroughly artificial, 

 but eminently practical. Thus by his two immense reforms and by 

 his ingenious system of classification, Linnaeus reached a point 

 where, consciously or unconsciously, he became a dictator in many 

 departments of natural history. It must be remembered further, 

 that his authority was greatly augmented by the wide range of his 

 activities, for he lived and worked before the days of specialization. 

 Hence he could give to the world a " Systema Naturae." 



In his reforms and in his provisional system he made use of two 

 units, the individual and the species. The individual is the unit of 

 description, the species is the unit of classification. Both of them 

 presented curious difficulties of definition. Thus an individual is 

 usually defined as a thing or an organism which cannot be separated 

 into parts without losing its identity. But if we take an individual 

 plant, say, of rose, we can divide it into a hundred different pieces, 

 each of which is capable of independent growth. In the higher 

 animals, like man, for instance, and in a great many of the lower 

 plants, complete individuality is easily recognizable; but, on the 

 other hand, many of the lower animals and practically all of our 

 higher plants are communities rather than individuals. If any in- 

 dividuality at all exists, it is composite and corporate. The other 

 unit, the species, fares hardly better at the hands of one who tries to 

 define it strictly. If we take the definition already quoted from 

 Linnaeus or if we define it as " a perennial succession of individuals 

 perpetuated by generation," the determination of any given case 

 must be largely a matter of judgment, since, as a rule, the naturalist 



PROC. AMER. PHIL. SOC, XLVIII. I9I B*, PRINTED JULY 7, I9O9. 



