528 POPULAR SCIENCE MONTHLY. 



which analogy makes probable, the part played by prophecy is small. 

 Variation leads; the breeder follows. The breeder's method is to no- 

 tice a desirable novelty, and to work up a stock of it, picking up other 

 novelties in his course — for these genetic disturbances often spread — 

 and we may rest assured the method of nature is not very different. 



The popular belief that evolution, whether natural or artificial, is 

 effected by mass-selection of impalpable differences arises from many 

 errors which are all phases of one — imperfect analysis — though the 

 source of the error differs with the circumstances of its exponent. 

 When the scientific advocate professes that he has statistical proofs of 

 the continuity of variation, he is usually availing himself of that com- 

 prehensive use of the term variation to which I have referred. Statis- 

 tical indications of such continuity are commonly derived from the 

 study, not of nascent varieties, but of the fluctuations to which all 

 normal populations are subject. Truly varying material needs care in 

 its collection, and if found is often sporadic or in some other way un- 

 suitable for statistical treatment. Sometimes it happens that the two 

 phenomena are studied together in inextricable entanglement, and the 

 resulting impression is a blur. 



But when a practical man, describing his own experience, declares 

 that the creation of his new breed has been a very long affair, the sci- 

 entist, feeling that he has found a favorable witness, puts forward this 

 testimony as conclusive. But on cross-examination it appears that the 

 immense period deposed to seldom goes back beyond the time of the 

 witness's grandfather, covering, say, seventy years; more often ten, or 

 eight, or even five years will be found to have accomplished most of 

 the business. Next, in this period — which, if we take it at seventy 

 years, is a mere point of time compared with the epochs of which the 

 selectionist discourses — a momentous transformation has often been 

 effected, not in one character but many. Good characters have been 

 added, it may be, of form, fertility, precocity, color and other physio- 

 logical attributes, undesirable qualities have been eliminated, and all 

 sorts of defects ' rogued ' out. On analysis these operations can be 

 proved to depend on a dozen discontinuities. Be it, moreover, remem- 

 bered that within this period, besides producing his mutational charac- 

 ter and combining it with other characters (or it may be groups of 

 characters), the breeder has been working up a stock, reproducing in 

 quantity that quality which first caught his attention, thus converting, 

 if you will, a phenomenon of individuals into a phenomenon of a mass, 

 to the future mystification of the careless. 



Operating among such phenomena the gross statistical method is a 

 misleading instrument; and, applied to these intricate discriminations, 

 the imposing correlation table into which the biometrical Procrustes 

 fits his arrays of unanalyzed data is still no substitute for the common 

 6ieve of a trained judgment. For nothing but minute analysis of the 



