412 ON THE SUPPOSED BOTANICAL PROOFS OF THE 



the term at once loses its scientific value, which lies in the restricted 

 use. If generally used, it would mean no more than the word 

 'new'; but new characters may arise in various ways, by artificial 

 or natural selection, by the spontaneous variations of the germ, or 

 by the direct effect of external influences upon the body, including 

 the use and disuse of parts. If we assume that these latter 

 characters are transmitted, the further ' assumption of complicated 

 relations between the organs and the essential substance of the 

 germ becomes necessary ' (His), while the transmission of the 

 other kinds of characters do not involve any theoretical difficulties. 

 There is therefore obviously a wide difference between these two 

 groups of characters as far as heredity is concerned, quite apart 

 from the question as to whether acquired characters are really 

 transmitted. It is at all events necessary to have distinct terms 

 which cannot be misunderstood. His l has proposed to call those 

 characters which are due to selection 'changes produced by breeding' 

 ('erziichtete Abanderungen '), those which appear spontaneously 

 ' spontaneous changes ' (' eingesprengte Abanderungen '), and these 

 two groups of characters would then be opposed to those which he 

 calls 'acquired changes' ('erworbene Abanderungen'), of course 

 using the term in the restricted sense. Science has always claimed 

 the right of taking certain expressions and applying them in a 

 special sense, and I see no reason why it should not exercise this 

 right in the case of the term ' acquired.' It appears moreover that 

 this word has not always been used in this vague sense by patho- 

 logical anatomists, such as Virchow and Orth ; for Weigert and 

 Ernst Ziegler have employed it in precisely the same sense as that 

 in which it has been used by Darwin, du Bois-Reymond, Pfliiger, 

 His and many others, including myself. 



It is certainly necessary to have two terms which distinguish 

 sharply between the two chief groups of characters the primary 

 characters which first appear in the body itself, and the secondary 

 ones which owe their appearance to variations in the germ, how- 

 ever such variations may have arisen. We have hitherto been 

 accustomed to call the former ' acquired characters,' but we might 

 also call them ' somatogenic' because they follow from the reaction 

 of the soma under external influences ; while all other characters 

 might be contrasted as ' MutOffenief because they include all those 

 1 His, ' Unsere Korperform,' Leipzig, 1874, p. 58. 



