1887.1 ^^^ [Claypole. 



and function of variation, the existence of -wliich no naturalist can doubt, 

 be his explanation what it may. 



The second utterance of opinion to which I have alluded is contained in 

 a letter from Prof. Asa Gray, printed in " Nature " (Jan. 25, 1883). The 

 letter itself is written in reply to some remarks made by Mr. G. J. 

 Romanes in an article in the " Contemporary Review " for October, 1883. 

 It is difficult to quote any particular passages in exemplification of the views 

 of Prof. Gray, which are rather implied than expressed. The main point 

 of difference between the two writers is however the denial by Mr. 

 Romanes that "the facts of organic nature furnish evidence of design 

 other and better than any of the facts of inorganic nature," and the main- 

 tainance by Prof. Gray that this denial rests on no good foundation. In 

 some passages indeed the latter writer goes apparently even farther than 

 this merely negative position and implies, if no more, that in his opinion 

 variation has been beneficently guided by intelligence. It is difficult to 

 extract any other meaning from the following passage : " The evidence ot 

 design may be irresistible in cases where we cannot indicate its limits. 

 We can only infer with greater or less probability according to circum- 

 stances and especially according to relation to ends. Better evidence than 

 that of exquisite adaptation of means to ends is seldom if ever attainable of 

 human intention and in the nature of the case it is the only kind of evi- 

 dence which is scientifically available in regard to superhuman intention. 

 With what propriety then can it be affirmed that organic nature furnishes 

 no other and no better evidence of underlying intelligence than inorganic 

 nature? The evidence is certainly other and to our thinking better." 



It seems impossible to attribute to the author of this passage any inten- 

 tion other than that already expressed ; viz. : that alongside of the capacity 

 for variation there acts some power guiding the ensuing actual variation 

 along a definite course to a definite end. 



If any doubt yet exists concerning Dr. Gray's meaning, such doubt 

 must be altogether removed by the following extract. In a notice of Dr. 

 Carpenter's paper in the "American Journal of Science, " for April, 1884, 

 Prof. Gray says : 



"Variation has been led along certain beneficial lines like a stream 

 along certain definite and useful lines of irrigation." 



The expression "has, been led" is rather indefinite, but can scarcely 

 mean less and may mean much more than I have above attributed to its 

 author. To assert that variation has been led along definite lines implies 

 the coaction of some guiding power. To assert that these lines are always 

 beneficial to the variant organism implies a postulate of vast magnitude 

 and one whose admission is infinitely difficult in face of the phenomena of 

 organic nature. 



II. 



Definition of Terms. 

 The purpose of this paper is in the first place to examine so much of the 

 evidence of nature on this point as shall be sufficient to show that the 



