76 
Skene .— The Acidity of Sphagnum and its 
A method described by Czapek (’ 99 ) for getting rid of cell contents 
was tried. It consists in boiling under the reversed condenser first in ether, 
then in alcohol, and finally in distilled water. Such substances as fats and 
chlorophyll are thus removed. The treatment has no effect on the acid 
nature of the plant. 5 . acutifolium gave a strong reaction with sodium 
chloride after the treatment. 
The cell contents, including the protoplasm, may be almost entirely 
removed by chloral hydrate (5 parts to 2 aq. dist.). S. rubellum was 
digested with chloral hydrate for ten days, thoroughly washed out, and then 
tested for acid. The results were : 
Untreated, 0*0947, 
Treated, 0-0625. 
Examination under the microscope showed only shrivelled remains of the 
cell contents. The acidity is reduced to two-thirds, and this at least must 
be due to substances in the cell-wall. It is probable that the third, which 
has disappeared, is not due to cell contents, but to cell-wall also ; for 
this must undergo some alteration under the influence of the powerful 
reagent. 
III. Occurrence of the Acid Reaction in other Plants. 
Baumann and Gully state that several other Mosses have the same 
properties as Sphagnum. I tested a number of Mosses with 5 per cent, 
salt solution and obtained the reaction with Polytrichum strictum , P. com¬ 
mune , Leucobryum glaucum , Hypnum splendens , Hylocomium loretim ; 
Fontinalis antipyretica gave a faint reaction. In addition to these, the 
Lichens Parmelia laevigata , Evernia furfur acea, E. prunastri , Usnea 
barbata , all gave a strong reaction. No reaction, on the other hand, was 
given by Mnium hornum , Neckera pennata , N. crispa , Hylocomium tri- 
quetrum , Leucodon sciuroides. 
The reason for the negative result may be threefold, (a) The acid 
compounds of the moss may be saturated already. Leucodon , after washing 
out with C 0 2 water, gave a strong reaction, while the reaction of Fontinalis 
was increased. Weissia viridida , a chalk Moss, could be freed from adhering 
particles only by washing with dilute HC 1 , and then water; thereafter it 
gave a strong reaction, (b) Those objects which have a low acidity may 
be unable to liberate sufficient HC1 from sodium chloride (an unfavourable 
salt) to give the reaction. The behaviour of different Sphagna illustrates 
this. Salt solution in which S', rubellum has been soaked gives a very 
strong reaction; if S. recurvum has been used the reaction is less marked, 
while after S. contortum it is slight. With contortum which has been 
washed it is stronger. ( c ) There is, in the third place, the possibility of 
a specific difference between the acid substances in different plants. 
