HEREDITY 205 



human breed, we have, of course, to remember that our race 

 has not got beyond the scope of natural selection, much as we 

 try to evade it." It is well that the large audience to wliich 

 Professor Thomson's book will appeal should be reminded that 

 the Stygian gulf of life cannot be crossed except by such who can 

 pay Charon his ferry fee. It might not have been amiss, perhaps, 

 if our author had pointed out that had we been brave enough in 

 the past to have left Natural Selection unfettered, we need not 

 to-day have burdened ourselves with " eugenic consciences," 

 with amended " marriage licenses," with costly schemes of 

 " preventive medicine," and a " spreading enthusiasm for 

 health." To us, it appears preferable to see a community that 

 does not care whether the haciUus communis coli is in its corporate 

 intestines or not, to one composed of indi\dduals always counting 

 their pulses and swallowing lactic-acid tablets ! Picture the two 

 types : the one man spontaneously happy, vigorous, indifferent 

 to germs, while the other wastes the hours of life standing by 

 the brink of its waters shivering from fear and incapable of 

 plunging ! And yet it is this latter type that our " enthusiasm 

 for health" and schemes of " preventive medicine" are rearing 

 fast. Professor Thomson's warning is in season, and it is to be 

 solemnly hoped that they who feel the glow of his golden sunsets 

 will not forget that upon the other horizon, under cover of the 

 rising darkness, a devastating storm is following the sun. 



While, here and there, the author thus expresses a salutary 

 warning, not infrequently his hopes appear to be too much of 

 the ethereal order. When, for instance, he tries to persuade his 

 readers that it is possible to escape, in some measure, the inexor- 

 able hereditary persistence of congenital defects, by the same 

 mechanism that sometimes causes a desirable or favourable varia- 

 tion to be lost, he is approaching dangerously near to " building 

 castles in the air." That such a thing may be possible is not of 

 course disputed. But such negative variations are, as far as our 

 present e^ddence instructs us, exceedingly rare, relatively to the 

 number of times in which such characters persist. We have 

 only to recall such a pedigTee as that of JVfr. Nettleship's stationary 

 night blindness, where a defect persisted through ten generations 

 for a period of 270 years, and still exists, to perceive that it is not 

 along that line of Nature's processes we can hope for any 

 amelioration of human suffering. There is danger in arousing 

 such expectations and in building above earth. Careless readers 

 — and how many there are — will believe that it is possible to 

 stop the sun of heredity at noon-day, and to reverse its inevitable 

 onward, westward march. Alas ! it is harsh, perhaps, but better 

 to emphasize the lesson that while there may be occasionally a 

 tumultuous sun-spot on the sun, the relative motion of which may 



