146 THE ORIGIN AND EVOLUTION OF LIFE 



The Lamarckian view that adaptation in the body cells invari- 

 ably precedes similar adaptive reaction in the chromatin is not 

 supported either by experiment or by observation; such pre- 

 cedence, while occasional and even frequent, is by no means 

 invariable. The Darwinian view, namely, that chromatin 

 evolution is a matter of chance and displays itself in a variety 

 of directions, is contradicted by palaeontological evidence both 

 in the Invertebrata and Vertebrata, among which we observe 

 that continuity and law in chromatin evolution prevails over the 

 evidence either of fortuity or of sudden leaps or mutations, that 

 in the genesis of many characters there is a slow and prolonged 

 rectigradation or direct evolution of the chromatin toward adaptive 

 ends. This is what is meant in our introduction (p. 9) by 

 the statement that in evolution law prevails over chance. 



Visible Characters, Invisible Chromatin Determiners 



The chief quest of evolutionists to-day in every field of 

 observation is the mode and cause of the origin and subsequent 

 history of single characters. The quest of Darwin for the causes 

 of the origin of species has now become an incidental or side 

 issue, since, given a number of new or modified heredity char- 

 acters,^ presto, we have a new species. In this present aspect 

 of research the discoveries of modern palaeontology are in 

 accord with many of the recently discovered laws of heredity. 

 The palaeontologist supports the observer of heredity in dem- 

 onstrating that every vertebrate organism is a mosaic of an 



' Character (Greek, xapax.TTjp, metaph., a distinctive mark, characteristic, character) 

 is the most elastic term in modern biology; we may apply it to every part and function 

 of the organism, large or small, which may evolve separately and be inherited separately. 

 Mendel has shown that "characters" are far more minutely separable in the invisible 

 chromatin than they are in the visible organism; also that every bodily "character" is 

 a complex of numerous germ "characters," which are technically known as determiners or 

 factors. For example, such a simple visible character as eye color in the fruit-fly is known 

 to have determiners in the chromatin. Morgan, Thomas Hunt, 1916, pp. 118-124. 



