338 SCIENCE PROGRESS 



from them, there is never any appeal to the metaphysical, nor 

 does he allow sentiment to gloss over facts. 



In the case of Prof. Thomson's book these matters are dealt 

 with in a very different way. He appears to me to belittle facts 

 and to enlarge sentimentality ; he shows frequently that he 

 places reliance in what, as far as I can make out, is a meta- 

 physical directive power in evolution ; though he has not 

 formulated this definitely, as Bergson does, he has very decided 

 leanings in that direction. A not inconsiderable number of 

 biologists, most unfortunately, are inclined to somewhat similar 

 opinions. Prof. Thomson lays great stress upon the danger of 

 adopting legislative measures of limiting the breeding of the 

 unfit, because many variations are " unknown quantities"; be- 

 cause "the unpromising bud may burst into a fair flower"; 

 because evil traits may work themselves out ; because many bad 

 traits may be due to modifications produced in the individual 

 by the environment (he quotes the Jukes as a possible example 

 of the modificational effect of " social ostracism ") ; and because 

 " preoccupation with the biological outlook — the breeder's point 

 of view — will undoubtedly lead to fallacy upon fallacy, the 

 1 materialisms ' to which we have already referred." 



If we take facts as they are, there can be no doubt that there 

 is a constant interchange between the various grades of indi- 

 viduals in the civilised state. Variations towards mental and 

 physical inferiority tend to cause a fall, and vice versa. The 

 mortality in the lowest class is higher than in any other, and 

 thus provides a process of elimination acting most forcibly upon 

 the most undesirable part of the population. But modern 

 sentimental legislation is altering all this. The mortality per 

 thousand has fallen greatly all over the country, in the town 

 population particularly. Dr. Chalmers recently gave an analysis 

 of the mortality in the population of Glasgow. This shows that 

 the mortality has fallen 19/4 per cent, during the past ten years, 

 but that the greater part of this fall has been in families living 

 in one or two rooms. The mortality of that part of the popula- 

 tion consisting of families living in four rooms or more has 

 remained practically unchanged. This gives one seriously to 

 think, for it means that a most necessary form of selection is 

 ceasing and nothing is taking its place. 



It is quite certain that any form of selection may occasion- 

 ally destroy desirable individuals, but this cannot be the usual 



