PLEOMORPHISM OF THE SCHIZOPHYTA. 503 
Thus writes Prof. de Bary in 1884. To some extent I have 
reason to thank him for the recognition which he gives to my 
position in this matter. But I cannot think that he has 
given a correct statement of my relation to the conclusion 
which he finally adopts when he associates me with Lister, 
who derived Bacteria from Fungi, with Billroth, who massed 
all Bacteria under one collective species, and with Nageli, who 
declared that he did not see grounds for distinguishing as 
many as two. 
The view which I put forward in 1873 is precisely that 
which Prof. de Bary now espouses, and I think I may very 
rightly object to its being confounded with the extreme and 
exploded theories of other naturalists. As to the “strict 
morphological and developmental researches ” which now have 
made my doctrine of the pleomorphism of the Schizophytes 
acceptable to Prof. de Bary, I beg to point out that they do 
not differ in character from my own researches on Bac- 
terium rubescens. Prof. de Bary very properly cites the 
later researches of Cienkowski, Neelsen, Hansen, and Zopf, as 
the chief amongst those which have tended to establish that 
view as to the forms and species of Schizophyta which I pro- 
mulgated in 1873. They have done so, not by affording us 
any stricter evidence of actual observation of change of form 
taking place under the observer’s eye, but by multiplying cases 
similar (in regard to the kind of observation made) to that 
published by me in 1873, viz. observations of the juxtaposition 
and structural continuity of different forms, and of the co-exist- 
ence with extremely divergent forms of abundant intermediate 
forms. 
In relation to the attitude taken up by one of the above- 
named observers, I have something further to say. Dr. Zopf 
has made valuable researches on various Bacteria and on the 
Mycetozoa, and has published the best systematic account of 
each of these groups which has appeared. In his quarto 
memoir (Leipzig, 1882) on the Schizophyta, as well as in the 
smaller handbook which he has since produced, Zopf gives a 
reference to my memoir on “A Peach-coloured Bacterium.” 
