668 APPENDIX B. 



Though the counter-opinion of one who is not a naturalist (as 

 Professor Weismann points out) may be of relatively small value, 

 yet I must here again give it, along with a final reason for it. 

 And this reason shall be exhibited, not in a qualitative form, 

 but in a quantitative form. Let us quantify the terms of the 

 hypothesis by weights ; and let us take as our test case the rudi- 

 mentary hind-limbs of the whale. Zoologists are agreed that 

 the whale has been evolved from a mammal which took to 

 aquatic habits, and that its disused hind-limbs have gradually 

 disappeared. When they ceased to be used in swimming, natural 

 selection played a part — probably an important part^ — in decreas- 

 ing them ; since, being then impediments to movement through 

 the water, they diminished the attainable speed. It may be, too, 

 that for a period after disappearance of the limbs beneath the 

 skin, survival of the fittest had still some effect. But during the 

 latter stages of the process it had no effect ; since the rudiments 

 caused no inconvenience and entailed no appreciable cost. Here, 

 therefore, the cause, if Professor Weismann is right, must have 

 been panmixia. Dr. Struthers, Professor of Anatomy at Aber- 

 deen, whose various publications show him to be a high, if not 

 the highest, authority on the anatomy of these great cetaceans, 

 has kindly taken much trouble in furnishing me with the need- 

 ful data, based upon direct weighing and measuring and estima- 

 tion of specific gravity. In the Black Whale [Balcenoptera horealis) 

 there are no rudiments of hind-limbs whatever : rudiments of the 

 pelvic bones only remain. A sample of the Greenland Right 

 Whale, estimated to weigh 44,800 lbs., had femurs weighing 

 together 3^ ozs. ; while a sample of the Razor-back Whale 

 {Balcenoptera musculus), 50 feet long, and estimated to weigh 

 56,000 lbs., had rudimentary femurs weighing together one ounce ; 

 so that these vanishing remnants of hind-limbs weighed but one- 

 896,000th part of the animal. Now in considering the alleged 

 degeneration by panmixia, we have first to ask why these femurs 

 must be supposed to have varied in the direction of decrease 

 rather than in the direction of increase. During its evolution 

 from the original land-mammal, the whale has grown enormously, 

 implying habitual excess of nutrition. Alike in the embryo and 

 in the growing animal, there must have been a chronic plethora. 

 Why, then, should we suppose these rudiments to have become 

 smaller ? Why should they not have enlarged by deposit in 

 them of superfluous materials ? But let us grant the unwarranted 

 assumption of predominant minus variations. Let us say that 

 the last variation was a reduction of one-half — that in some in- 

 dividuals the joint weight of the femurs was suddenly reduced 

 from two ounces to one ounce — a reduction of one-900, 000th of 

 the creature's weight. By inter-crossing with those inheriting 



