LETTER XV. 



161 



developed for a particular purpose," possess no more 

 vitality than those portions of them which, from time 

 to time, for your particular convenience and comfort, 

 you pare or crop. That it is in this sense and no 

 other that Dr Carpenter does or can speak of the 

 continued vitality of the general cellular basis, may 

 be inferred from his known views as to the very 

 transient duration of vitality in any organised struc- , 

 ture. And that it is, is clear from a more specific 

 statement which he makes in regard to trees : — 



"There need not be the least difficulty in admitting the 

 continued vitality of the general cellular basis of the stem of 

 an ordinary tree, notwithstanding that it may have attained 

 the age of some hundreds, or even thousands of years. The 

 parts Jirst formed may have long since decayed away^ but a 

 new growth is continually taking place." * 



9. I mentioned that, in connection with the general 

 statements now before us, Dr Carpenter adduces two 

 specific instances in opposition to my theory. Let us 

 see whether they embrace anything not contained in 

 those general statements. The first is that of an 

 Elm :— 



An Elm- tree, which grew to the height of nearly thirty 

 feet before it gave off any branches, had its upper part entirely 

 broken off in a gale of wind, and the stem was left standing, 

 entirely bare of foliage. Its death was considered almost 

 inevitable (and such it was upon Dr Harvey's theory ;) but it 

 was thought desirable to give it a chance of recovery, and 



* Ibid. p. 904. 

 L 



