( 580 ) 
the “primare Wandlamelle” of the medullary ray cells was according 
to Janse all that had been stained. 
In my experiments with living branches the staining extended not 
only to the tori of the vessels aqd fibres, but also to those of the 
half bordered pits between the medullary ray cells on the one side 
and the vessels and fibres on the other side; the contents of the 
medullary ray cells however remained colourless, as stated above. 
The results of other experiments carried out by me, agree well 
with these facts. Instead of taking dead branches, I caused to ascend 
in living branches a l / 10 % solution of Saureviolett in strong alcohol, 
and also a V 10 solution in water containing 4 % formaldehyde. 
As controls I employed living branches in a 7 10 % solution of 
Saureviolett in water. 
I now found that the living branches in the poisonous solutions 
were stained practically in the same way as the dead branches in 
innocuous ones, only not so completely. It was clear that the alcohol 
and the formaldehyde only gradually exercised their fatal action on 
the plant. The tori were always unstained; only a few were 
stained very faintly. The walls generally showed a uniform staining; 
the medullary ray and parenchyma cells with contents were coloured 
dark blue. 
Finally I may add that microscopical transverse sections through 
living branches, which sections were afterwards placed for 20 horn’s 
in an aqueous Saureviolett solution of 7io °/o, were stained quite 
uniformly dark blue, exactly in the same way as those sections 
made after the stain had ascended in dead branches; the colour was 
only somewhat more intense. The transverse sections through control 
branches, which had previously stood in the same solution for 4 
days, on the other hand showed, as was to be expected, a staining 
quite similar to that which was described above for living branches. 
Description of the experiments . 
Experiment IY. 
Fagus siJvatica. 
A living leafy twig, about 4 mm. thick at its base, stood for 9 
days in a solution of Saureviolett. The stain ascended to the top 
and into the leaves. The bark, the cambium and the pith remained 
quite unstained; the staining was limited to the wood and here the 
stain was only in the inner layer (adjoining the lumen) of the walls 
of vessels and fibres; the tori of the bordered pits were stained a very 
