THE BENGUET IGOKOTS. 463 



The simplest explanation, of all the phenomenal variations heretofore 

 presented seems to be that the Igorot has been isolated long enough to 

 reach the amalgamated stage of no Mendelism. 



The unit characters in all individuals have not blended, but occa- 

 sionally manifest the character of the original type in a diversified way 

 as represented by the nine Igorots, and not infrequently an individiual 

 of almost pure type appears, who is a true European (Martin). These 

 are but relics of a departed Mendelism. 



Efforts to reconcile Mendel's laws with the prevailing views of blended 

 effects in heredity need not be unavailing, if the two may be considered 

 as phases of the same process acting at different times during the life 

 history of an elementary species. 



Heredity represents all the changes of organic life by three factors (5) : 



1. Determinants, which are in the germ plasm; 



2. Modifiers, which are all influences through time and space that act on the 

 germ plasm; and 



3. Laws of change, which are the rules of conduct by which the determinants 

 and the modifiers interact. 



These factors are variable when looked at through all space and during 

 all time, but for any elementary species in a given space and for a 

 limited time they are fixed. 



D and R (fig. 13) represent homozygotes of an allelomorphic pair that meet 

 at 1 in sexual union, begin to blend at 2, present the picture of a variable blend 

 at 3, and fuse completely into a perfect blend at 4. A cross section of the 

 diagram above line 3 represents the relative number of individuals of the 

 diiTerent kinds presert at that time. The width of the diagram also indicates 

 the amount cf variation at any time. D=homozygous dominants; R=homozy- 

 gous recessives; DR=heterozygotes; B '=a variable blend ever increasing in 

 number with each successive generation; while D, E, and DR decrease to dis- 

 appear entirely at 3. B - represents the continuation of the blend without either 

 of the originals of the allelomorphic pair, but with all shades of intervening 

 characters blending in various ways as infiueneed by ancestry and by enviroment, 

 until a homozygote is formed at 4. 



From 1 to 2 true Mendelism exists, spurious Mendelism is found from 2 to 3, 

 and from 3 to 4 no Mendelism is present but two tendencies prevail, (a) the 

 reversion to type, and (6) the tendency to blend. 



The three Mendelian (?) conditions may exist at the same time in 

 a single individual, one character exhibiting true Mendelism, another 

 false and a third no Mendelism, or only one condition may be present 

 at one time. 



Davenport and Davenport (13) have established true Mendelian hered- 

 ity for eye color in man; Bateson(2) has designated many conditions in 

 man which indicate spurious Mendelism; and Boas (7, 8, 9, 10) has sug- 

 gested the two hereditary tendencies above mentioned {a and b) when 

 broad headed and long headed or wide faced and long faced individuals 

 are united in marriage. 



