AN INTRODUCTORY ORIENTATION 7 



will become impressed, if he has not been so before, with the 

 numerous pitfalls into which the student of human evolution is 

 liable to fall. The literature on the subject is full of conclusions 

 based on inadequate evidence, yet put forth with a confidence 

 which in itself should engender a suspicion of their soundness. 

 But the most disappointing feature of the situation is the dearth 

 of facts upon which safe deductions can be based. Demographi- 

 cal statistics have been kept only for a relatively short period of 

 time; and anthropometric data have not been gathered on a scale 

 sufficiently extensive, or over a period sufiiciently long, to give us 

 an idea of the trend of development in any considerable group of 

 men. Data compiled at different times and places are often not 

 comparable for want of common standards. If we wish to deter- 

 mine, in what ways the population of any country has been 

 changed we encounter almost insuperable difiiculties. The 

 Parliamentary Committee appointed a few years ago to investi- 

 gate the alleged physical deterioration of the people of Great 

 Britain, after making an exhaustive enquiry, could come to no 

 conclusion as to whether such deterioration had actually occurred. 

 Of course this result is of little value in proving the absence of 

 physical degeneracy in recent times. It is perfectly consistent 

 with the view that such degeneration has even been rapid. It is 

 simply a confession that the data are insufficient for the solution 

 of the problem. 



But if we are lacking in records which tell us in what direction 

 human beings have actually been changed, we can at least ascer- 

 tain something of the action of the forces which are now at work 

 in modifying the inherited qualities of the race. We can observe 

 in a measure how things are actually going on. We can trace the 

 way in which hereditary traits are transmitted; we can study at 

 first hand the action of natural selection in eliminating ill adapted 

 strains of humanity; we can determine the relative degrees of 

 rapidity with which different stocks reproduce themselves, and 

 we can ascertain something of the action of the various selective 

 forces which have arisen as a result of the development of human 

 institutions. Where the data which are being accumulated are 



