72 J. H. Priestley and Dorothy Armstead 
Fuchsia. Our first thought was organic acid, but tested with the 
usual series of indicators (Cole (6), loc. cit. p. 22) the P H value of the 
sap in the vines was practically that of true neutrality. No calcium 
salts could be precipitated from the concentrated juice, so that in 
particular any soluble salts of oxalic acid seemed to be absent. This 
was a surprise to us because parallel experiments in progress in the 
laboratory by Miss L. Woffenden had drawn attention to the fact 
that the hydathodes of Fuchsia gradually become blocked with an 
amorphous deposit which behaves like calcium oxalate; and that in 
the neighbourhood of the hydathodes of many plants, crystalline 
deposits of calcium oxalate are abundant. 
An arrangement was devised by which the liquid from the vines, 
after concentration under reduced pressure, could be continuously 
extracted by ether. The ether was purified by redistillation after 
standing over stick potash for several days, a precaution that experi¬ 
ence proved essential. From the ether extract, on evaporating, a 
substance separated out either in thin plates or needles with serrated 
margins. The substance crystallised best from chloroform. This sub¬ 
stance is readily soluble in warm ether, sparingly soluble in cold, 
and has a slightly pungent odour faintly reminiscent of condensation 
products of formaldehyde. This fact led us to apply Rimini’s test as 
modified by Schryver( 23 ) with the result that the substance, whilst 
giving no reaction for free formaldehyde, gave a very strong reaction 
for formaldehyde in combination. We are unable at present to give 
any clearer indication of the nature of this substance and indeed 
should be very grateful for suggestions. In any case it cannot be the 
only other organic compound present besides sugar, as from 800 c.c. 
of the original sap, concentrated under reduced pressure and then 
continuously extracted with ether, a yield of only 0-08 gm. was 
obtained. As some 0-06 per cent, of organic substance has to be 
accounted for in the vine sap, obviously some other compounds are 
present. 
Solutes in sap exuded by stems or leafy branches 
Liquid exuded by the activity of stems or leafy twigs under the 
conditions described in a preceding section (p. 64) may also be 
expected to contain organic substances, but as the quantity of sap 
obtained in any particular experiment is not large, it is not possible 
to give very precise data as to their nature or quantity. Very varying 
results were obtained in the long series of experiments conducted 
under this head, and they are probably not worth detailed analysis. 
