122 HEREDITARY CHARACTERS 



unchanged or so little changed that the difference escapes 

 our observation. 



Bearing all these facts in mind, we have an explanation 

 for the transmission of the bulk of the characters of the race 

 in Nageli's idioplasm theory in its simplest form, in con- 

 junction with recapitulation and regression. This involves 

 but little in the way of assumption. Recapitulation is in 

 the individual a demonstrable fact, and the idioplasm theory 

 and regression assume hardly anything certainly no more 

 than is absolutely necessary in view of the facts at our 

 disposal. The assumption of morphological units for the 

 transmission of racial characters does not therefore seem 

 necessary. Indeed, it seems unjustifiable in view of some 

 of the evidence which we have already considered. 



If every racial character were represented by a morpho- 

 logical unit, all the gametes, from both male and female 

 parents, must contain every unit ; otherwise, it would be 

 impossible to account for the constant appearance of the 

 racial characters in every individual. But this would double 

 the units in every new individual, which seems unnecessary 

 waste, incompatible with the parsimony of nature. On the 

 theory here advocated, the only assumption is that the 

 gametes are formed of a particular kind of protoplasm which 

 has a potentiality of developing only along particular lines 

 in a particular manner, and this we know practically always 

 happens. If it does not, that individual collection of proto- 

 plasm perishes and does not reproduce its kind. With regard 

 to the individual variations, however, there are, as we shall 

 see later, some reasons to suppose that they may possibly 

 be represented by morphological units or entities. Some 

 of them are transmitted alternatively, and it would be 

 difficult to explain this without some such assumption. 



Apparently then the bulk of the characters are inherited 

 by the individual from comparatively remote ancestors. 

 The greater part of the variations occurring in the indi- 

 vidual are destined to be eliminated either at once or in 



