Beer. Development of the pollen grain and anther of some Onagraceae. 305 
The comparison which Meves has drawn between these 
deeply staining fibres of the tapetal cytoplasm and the chon- 
dromiten of certain animal cells is of tlie highest interest. 
In a large number of activelv functional cells, belonging to 
the most various tissues of the animal bodv, chromatic structures 
have been fonnd in the cytoplasm und described under the 
names of mitochondrien, chondromiten, pseudochromosomes, yolk- 
nuclei, cliromidien, apparato reticolare etc. 
Gloldschmidt 1 ) has recently found good grounds for grou- 
ping all these structures togetlier and he has shown by direct 
experiment that at least in some cases (e. g. muscle-cells of 
Ascaris lumbricoides ) they are directly connected with the functional 
activity of the cell. 
In the tapetum the fibres (or their derivatives) unquestio- 
nablv play a prominent part in the cytoplasmic growth of the 
pollen-protoplasts and no doubt in the animal cell thev are also in 
some way associated with the elaboration of complex organic 
substances. 2 ) In this relation it may be recalled that several 
physiological chemists have pointed out the probability of 
nuclein or one of its constituent molecular groups forming a 
centre or starting point for the synthesis of complex organic 
matters in the living cell. 
The origen and Chemical nature of these chromidial struc¬ 
tures has, however, not yet been satisfactorily determined in all 
cases. In some cells which have been studied by Grold- 
schmidt it is highly probable that they are derived from the 
chromatin of tlie nucleus. 
I have shown above that the fibres in the tapetal cells of 
Genoth era possess a nuclear origen and may be referred to the 
transformation of the nucleoli and nuclear membranes. 
The staining reactions and the behaviour of these nucleoli, 
whilst the nucleus is still intact, show that they are, at least 
partly, composed of chromatin whilst the nuclear wall also seems 
to owe its affinity for nuclear dyes to the deposition of finely 
granulär chromatin upon its inner face or within its sub- 
stance. 
AYe see therefore that the fibres lying in the tapetal cyto¬ 
plasm are to a great extent derived from the chromatin of the 
nucleus and that much of the substance that ultimately passes 
into the pollen grains is a derivative of chromatin. 
The walls of the tapetum, during the greater part of the 
development of the anther are of a somewhat mucilaginous 
nature and can be very distinctly differentiated by raeans of 
an alkaline solution of congo red. In the older anther these 
1 ) G-oldschmidt, B. „Der Chroniidialapparat lebhaft funktionierender 
Gewebzellen“. (Zoolog. Jakrb. Abt. f. Anat. u. Ontogenie d. Tiere. Bd. XXI. 
1904. p. p. 1—100.) 
2 ) Tor example note tke relation which Matliews found to exist bet¬ 
ween tlie deeply staining fibres and the Zymogen granules of certain pan- 
creas and fixer cells. (Journ. Morphol. XV. Suppl. 1899.) 
