252 BEITRAGE ZUR MORPHOLOGIE UND PHYSIOLOGIE, ETC. 
which is, however, not yet clear. xperiments only gave negative 
1; 
c 
defined chromatophores which on treating with iron solution 
become chloroplasts, growing considerably as well as ecoming 
green. In the case of strong chlorosis it was often only possible to 
make out the chromatophores by aid of suitable stains 
not only unable to assimilate the carbonic acid of the atmosphere, 
but will not even form starch when supplied with a sugar solution; 
at any rate, will only do so in a very limited degree. 
spherical in form, or, in one case, the young leaves of Polypodium 
tricides, drawn out into rod-like structures. In size itis considerably 
smaller than the chloroplasts, but varies according to the species 
wide distribution, occu m families of Dicotyledons 
and Monocotyledons, in @) yptomeria elegans among the Conifere, 
Ceratozamia mexicana among the C d in five genera of true 
ferns. Its presence in the sses is uncertain, and in con- 
8 
contents of this interesting volume. For the rest we will only say 
that in two articles Dr. Zimmermann discusses the protein crystal- 
loid, its occurrence in various parts of the cell, and its distribution 
some cystolith-like swellings of the cell-wall in the epidermis of 
Cyperus alternifolius, composed of silica and cellulose; and on the 
