VII.] TRANSMISSION OF ACQUIRED CHARACTERS. 43 1 



" transient " (Weismann) characters acquired by the individual 

 can be transmitted ^.' 



The data upon which Hoffmann bases these opinions are 

 certain experiments conducted upon various plants, in order 

 to determine the conditions of hfe under which abnormal 

 flowers or any other variations occur most frequently: to 

 decide, in short, how far variations are caused by the change 

 of conditions. 



It is obvious that the attention of the author was not at first 

 directed to the question of the transmission of acquired cha- 

 racters. His experiments are of a much older date than the 

 present condition and significance of the question before us. 

 Hoffmann has, in fact, re-examined his former results from the 

 new point of view, and this explains wh}' his proofs are not 

 always sufficiently convincing when applied to the present 

 issue. But this is of no great importance, inasmuch as there 

 is no necessity for me to question the correctness of his 

 assumptions. 



The essential details of the experiments to which he directs 

 attention are as follows : — 



Different plants with normal flowers were subjected to greatly 

 changed conditions of life for a series of generations. They were, 

 for example, crowded together in small pots. Under these cir- 

 cumstances the plants were of course poorly nourished, and in 

 the course of generations, several species produced a variable 

 proportion of abnormal — viz. double-flowers. This, however, 

 was not always the case, for such flowers did not appear in 

 Matthiola annua and Helianthemmn polifoliiun. In other species, 

 such as Nigella damascena, Papaver alpinmn and Tagetes patiila^ 

 they appeared and often increased in numbers in the course 

 of generations, although this was not a constant result. For 

 instance, four successive generations o^Nigella dantascena, when 

 closely sown, produced the following results : — 



1883. No double flowers. 



1884. „ „ „ 



1885. 23 typical flowers : 6 double flowers. 



1886. 10 „ „ : I „ flower. 



^ I have used the expression 'transient' ('passant') in the same 

 sense as 'acquired,' in order to enforce the conclusion that they are 

 merely temporary, and disappear with the individual in which tliey 



