6o THE POPULAR SCIENCE MONTHLY 



already referred to ; it may be termed the genetic method, inasmuch as 

 it employs as its criterion of classification the demonstrable relation of 

 certain languages as divergent forms of some older form of speech. 

 As we have already seen, the linguistic stocks which we thus get as our 

 largest units of speech are too numerous to serve as the simplest pos- 

 sible reduction of the linguistic material to be classified. One naturally 

 turns, therefore, to a psychological classification, one in which the 

 classificatory criterion is the fundamental morphological type to which 

 a particular language or stock is to be assigned. Such a classification 

 of morphological types may proceed from different points of view, vary- 

 ing emphasis being laid on this or that feature of morphology. It is 

 clear at the outset that we have to distinguish between what we may 

 call the subject-matter or content of morphology and the mere form 

 pure and simple. Any grammatical system gives formal expression to 

 certain modes or categories of thought, but the manner of expression 

 of these categories or the formal method employed may vary greatly 

 both for different categories and for different languages. Not infre- 

 quently the same logical category may be expressed by different formal 

 methods in the same language. Thus, in English, the negative idea is 

 expressed by means of three distinct formal methods exemplified by 

 untruthful, with its use of a prefix un-, which Ccin not occur as a freely 

 movable word; hopeless, with its use of a suffix -less, which again can 

 not occur as a freely movable word; and not good, in which the nega- 

 tive idea is expressed by an element (not) that has enough mobility to 

 justify its being considered an independent word. We have here, then, 

 three formal processes illustrated to which may be assigned the terms 

 prefixing, suffixing and juxtaposing in definite order. While the same 

 logical category may be grammatically expressed by different formal 

 methods, it is even more evident that the same general formal method 

 may be utilized for many different categories of thought. Thus, in 

 English, the words books and worked use the same method of suffixing 

 grammatical elements, the one to express the concept of plurality, the 

 other that of past activity. The words feet and swam, furthermore, 

 respectively express the same two concepts by the use of an entirely 

 distinct formal method, that of internal vowel change. 



On the whole one finds that it is possible to distinguish between two 

 groups of grammatically expressed logical categories. One group may 

 be characterized as derivational ; it embraces a range of concepts ex- 

 pressed by grammatical elements that serve to limit or modify the 

 signification of the word subjected to grammatical treatment without 

 seriously affecting its relation to other words in the sentence. Such 

 merely derivational elements are, in English, prefixes like un-, suffixes 

 like -less, agentive suffixes like -er in baker, and numerous others. The 

 second group of logical concepts and corresponding grammatical ele- 



