420 ON SUPPOSED BOTANICAL PROOFS OF [VII. 



existent tree, and we are not therefore concerned, in this 

 method of propagation, with a succession of generations, but 

 with the successive distribution of one and the same individual 

 over many wild stocks. But no one will doubt that one and 

 the same individual can be gradually changed during the course 

 of its life, by the direct action of external influences. The 

 really doubtful point is whether such changes can be transmitted 

 by means of the germ-cells. If, as I presume, the English in 

 Ceylon do not care to eat wild cherries but prefer the cultivated 

 kinds, it follows that the branches which bear fruit in that 

 island have not been developed from germ-cells, at any time 

 since their introduction, and there is nothing to prevent them 

 from gradually changing their anatomical and physiological 

 characters in consequence of the direct influence of climate. 



Hence the instance which Detmer looks upon as plainly con- 

 clusive, can hardly be accepted in support of such a far-reaching 

 assumption as the transmission of acquired characters. 



It is therefore clear that none of the facts brought forward 

 by Detmer really afford the proofs which he believes that they 

 offer. But another botanist. Professor Hoffmann of Marburg, 

 well known for his long-continued experiments on variation, 

 has recently called attention to certain other botanical facts in 

 support of the transmission of acquired characters. These facts 

 are indeed conclusive, if we accept the author's use of the 

 term 'acquired,' but it will be found that they lead to hardly 

 any modification in the state of existing opinion upon the 

 subject. 



In a short note, dated Jan. i, 1888, the author communicated 

 to this journal (' Biologisches Centralblatt ') the statement that 

 changes in the structure of flowers caused by poor nutrition can 

 be proved to be hereditary to a greater or less extent ^. 



A more elaborate account of the experiments will be found 

 in several numbers of the ' Botanische Zeitung,' and the author 

 expresses his final results in the following words (see Bot. Zeit. 

 1887, p. 773) : — ' These experiments prove with certainty (i) that 

 insufficient nutrition may cause considerable morphological 

 changes (viz, qualitative variations) which are in the first place 

 acquired by the sexual apparatus of the flower, (2) that the 



^ Compare Biol. Centralbl. Bd. VII. No. 21. 



