..- . . . . s of .'.:. ' rc EVOI UTION 



don tliat 5-^f , : T represents the first of a line in which 

 a g en character appears). A new character or an 



additional increment of the same character, appears 

 in the sec stag* of acceleration "2." and is^epre- 

 sentc .: as b< :ore. by AJ*. the A ar . . ..: ing in the son: .. 

 and the j- being added to the ch.-.: . . : cr of the germ- 

 plasma. In the third Stage, the new character .: 3 ap- 

 pears in t: . s >ma, which now becomes S Tlu 

 acquired by the germ-plasma of the second stage, is 

 inherited by that of the third, which is therefore rep- 

 :;- ::ted : ( - . To the third stage is now added 

 the acquisition The : : is .-.gain incorporated into 



the soma of the sue;. . ding or fourth stage, which is 

 therefore i\ prc sentc ,: by the expression o .:"-.: while 

 the germ-r. ..>::... .: the same ^fourth. "4,") stage, is 

 : : --;nted : i -- . and so on. The lines of im- 

 mediate inheritance are represented by straight lines. 

 The vertical lines represent the descent of characters 

 from one type of the germ-plasma to a succeeding 

 one ; and the oblique lines represent the transmission 

 of the same characters to the soma into which it grows, 

 as the succeeding generation or stage. 



The letters j 1 . a- 9 etc. , expressive of characters ac- 

 quired by the germ-plasma, are numbered for identifi- 

 cation only. Should the influences derived from the 

 ancestry of the other sex be added to the diagram its 

 complexity would become inconvenient, and they are 

 therefore omitted. It is to be also observed, that the 

 enumeration of generations as immediately successive, 

 as 1-2-3 etc.. is to be understood as indicating succes- 

 sion only, and not any exact number of generations. 



In the hypothesis of heredity above outlined, it is 

 insisted that the effects of use and disuse are two-fold ; 

 viz.: the effect on the soma, and the effect on the 



