14 VARIATION 



this we conclude that the apparent make-up of the individual 

 depends upon the particular characters that happen to be 

 strongest, that is, most highly developed in his case, but that 

 he is in actual possession and may transmit any and all the 

 characters of the race to which he belongs, but no other. 



We now arrive at the distinction between dominant and latent 

 characters, which is as follows: Those characters that are prom- 

 inent in any individual are said to be dominant with him because 

 well developed and plainly evident, and all other racial charac- 

 ters are said to be latent because not evident, although they are 

 known to be present from the fact that they are transmitted to 

 the offspring, often becoming the dominant characters in future 

 generations. 



The term " latent" should not convey the impression of 

 hidden or lurking characters, but rather undeveloped possibil- 

 ities of the race within the individual in question. With this 

 conception the student will be saved much mental confusion 

 when dealing with heredity and reversion. 



Elementary characters. In a biological sense the ultimate 

 unit of variability, therefore, must be something less than the 

 racial characters which we have been discussing, because they 

 themselves are complex rather than simple. We speak of the 

 leg of a horse or the quality of milk as a whole. Even if we 

 narrow the point to the conformation of the hock or the propor- 

 tion of fat, we yet have characters clearly made up of parts. 

 The hock is an exceedingly complex structure, and seven, pos- 

 sibly nine or ten fats and oils are found in the fat of milk. 



As almost' unlimited color effects are made up by few pri- 

 maries in different proportions, and as all ordinary materials are 

 made up of a few chemical elements in different combinations, 

 so in all probability if we could make the ultimate analysis we 

 should find that all these characters are made up of definite liv- 

 ing units, that we may call, for want of a better name, elementary 

 characters. 



These elementary characters have received many and various 

 names. They are the stirp of Galton, the biophors of Weismann, 

 and the physiological units of biologists generally. In general 

 they are the smallest conceivable living units, comparable with 



