Beer. Development of the pollen grain and anther of some Onagraceae. "281) 
surrounded by a mucilaginous wall of pecnliar nature. In Epi- 
lobium tetragonum the primary sporogenous cells undergo a single 
longitudinal division so tbat two rows of motber-cells are foi - 
med wbilst in Oenothera a second longitudinal wall often follows 
the first so tbat eitber two or tree motber-cells are seen in tbe 
transverse section of each pollen sac. Tbe next important Step 
in development is tbe formation of a mucilaginous wall round 
eacb motber-cell. 
This wall is essentially similar to tbat wbich occurs in a 
corresponding position in ^otber angiosperms. Mangin 1 ) exa- 
mined tbe motber-cell wabs of a number of flowering plants 
and concluded, from tbeir microcbemical bebaviour, tliat tbey 
consist of callose in a peculiarly pure state. In Gentiana offici- 
nalis and Campanula rapunculoides Mangin 2 * ) noted some varia- 
tions in tbe composition of tbe (special-) motber-cell wall. 
From tbe facts sliat tbis wall, in tbe Onagraceae , stains 
deeply witb a solution ef corallin in soda (4°o Ma^CCb), vitli 
aniline blue, benzo-purpurin or congo red, tbat is gives none of 
tbe cellulose reactions witli lodine reagents and is insoluble in 
cuprammonia. and tbat it bas no affinity for rutbenium red. 
I agree witb Mangin in considering callose to be its only con- 
stituent. 
In several respects, bowever, I find tbe reactions of tbe 
motber-cell wall to disagree from tliose usually attributed to 
callose. Callose is described as readily soluble in 1 0 o caustic 
potasb or soda. I find tbis statement to require some modifi- 
cation witb regard to tbe motber-cell wall. Tbe motbei- 
cell wall of fresb material of Äucuba japonica dissolved 
witb exemplary rapidity in 1 % caustic soda but I bave kept 
microtome sections of material of Oenothera fixed witb I 1 ent¬ 
min g’s solution for over an liour in 1% caustic potasb and still 
found tbe motber-cells undissolved at tbe end of tbat time. 
Tbe motber-cell walls of fresb material of 0. bienms liad onk 
disappeared after nearly 24 bours in 1 °/o Ha OH. I ba^e found 
fresb material of tbe pollen-motber-cells of tbe Horse-cbestnut 
equall} 7 ' resistant to 1 % caustic alkali. In 10 0 o caustic potasb 
tbe motber-cell walls of Oenothera soon disappear. It will be 
seen from tbese remarks tbat tbere is some x anation in tbe 
solubility of tbe motlier-cell wall in dilute caustic alkalm 
Mangin bas affirmed tbat callose is soluble in pbosplioric 
acid but I liave left tbe motber-cell walls of Oenothera biennis 
for many liours in strong pbosplioric acid witb out obtaining any 
signs of tbeir solution. Napbtol black, m acid solution, is said 
by Mangin to Stain cellulose but to leave callose uncolouied. 
I liave obtained precisely tbe opposite result. Bismarck brovn, 
1) Mangin, ,,Observations snr la membrane du Ctrain de Pollen mm . 
(Bull. Soc. Bot. d. Prance. T. 36. 1889.) 
2) Mangin, „Observations snr le developpement du polien , \ (Jdiiü. 
Soc. Bot. d. France. T. 36. 1889.) 
