96 PLANT ANATOMY. 
yellowish-brown * by iodine,* rose-red by Millon’s reagent, violet 
by Trommer’s reagent, and red by sugar and sulphuric acid. 
Dead protoplasm abundantly absorbs coloring substances (espe- 
cially fine with eosin). Imbedded in the protoplasm of young 
cells (Fig. 27), or suspended by threads of protoplasm (Fig. 28, 
b, c), there is found the nucleus (Fig. 27 a, and Fig. 28), which 
mostly occurs singly. The nucleus possesses one or two nucleoli 
(Fig. 27 5), and consists likewise, for the most part, of a proto- 
plasm-like substance, in which, however, the nuclein is con- 
tained ina granular form. By treatment with coloring sub- 
stances (hematoxylin, aniline-green, alum-carmine), the nuclei 
are rendered more clearly visible. 
Since the protoplasm has contracted in old cells to the mini- 
Sear 
Fic. 28.—The process of cell division schematically represented in its individual phases 
(Hartig). : 
mum and the-nucleus has entirely disappeared, both of these play 
but a subordinate part in pharmacognosy, which occupies itself 
mostly with organs consisting of completely developed tissues, 
notwithstanding the importance of the protoplasm in the econ- 
omy of the plant itself, and in the estimation of the value of 
herbs as fodder. 
‘ All protein substances are colored yellow by iodine, thus protoplasm, 
gluten, protein crystalloids (for the latter, iodine in glycerin is em- 
ployed), the fundamental portion of the chlorophyll granules, etc. 
* For these micro-chemical reactions, the compilation by Poulsen may 
be highly recommended (‘Botanische Microchemie,” Cassel, 1881. 
American edition by Trelease, see page 49). Compare also Tschirch, 
_ ‘Microchemische Reactionsmethoden im Dienste der technischen Micro- 
scopie,” Archiv der Pharm.,, 1882. 
