INFLUENCE OF ORDER OF BIRTH, ETC. 307 
child that lived for 35 or more years. Now, suppose that in 1910 
we select a group of individuals from the families of twelve in the 
population. It is obvious that our group would contain many 
more of the twelfth born from the old families than from the later 
ones. It is evident from these considerations that when we sim- 
plify the problem of handicapping the first born by considering 
the ordinal position of the marked member within families of a 
particular size, we do not avoid all statistical pitfalls. Our data 
collected by the methods generally employed would be affected 
by increase of population and decline of the birth rate, to say 
nothing of other possible factors. 
Mention may be made of one circumstance which might make a 
real difference between the first and subsequent members of a 
family,—and tbat is inherited syphilis. It is a well-known fact 
that the early born are most seriously injured by this disease. 
The not uncommon history of a syphilitic family is first the 
occurrence of one or more abortions, then the birth of weakly 
children and finally the production of children who are com- 
paratively healthy. The inclusion of any considerable number 
of such family histories would tend to cause the first born to 
occupy an unenviable position. Since syphilis predisposes the 
patient to tuberculosis there would tend to be an exaggeration 
of the latter disease and probably also insanity and other patho- 
logical defects among the early born. 
So far as pure heredity is concerned we should naturally 
expect the first born to have the same endowments as the sub- 
sequent members of the family. Primacy of birth as Auerbach 
remarks is ‘‘Kein vererbungstechnischer Begriff.” Whatever 
effects may be due to maternal immaturity or the difficulties 
incident upon bearing the first child are to be regarded as somatic 
phenomena which there is no reason to believe produce any 
inherited effect. How long it takes for initial handicaps which 
are observed to preponderate in first born children to be out- 
grown, or whether they are ever outgrown, we are unable to 
decide. 
Those who occupy the position of first rank in their families 
