Physiological Studies in Plant Anatomy 71 
This result is interesting if compared with the results of the 
analysis of Fraction I. It will be seen that the amount of organic 
matter has fallen off considerably. This is what would be expected, 
as the supply of storage carbohydrates in the parenchyma surround¬ 
ing the vessels will have been very much depleted. The organic 
residue obtained, however, as in the previous case, is larger than the 
figure for sugar obtained by the reduction of Fehling’s. It is also 
interesting to note that the amount of inorganic matter is practically 
the same as before. As the amount of liquid exuded by the root 
gradually diminishes, the organic substances present also decrease, 
whereas the inorganic remain constant, from which it would seem 
that the amount of liquid passed into the xylem from the surrounding 
tissue was dependent to a much greater extent upon the concen¬ 
tration of organic than of inorganic solutes in the sap. 
Kastle and Elvove(i 5 ) had found nitrite present in the liquid col¬ 
lected by them in root pressure experiments with Fuchsia, an observa¬ 
tion we had confirmed, so that the liquid from the vine was tested 
for nitrite with acidified solution of potassium iodide and starch. 
The sterile liquid gave a very strong reaction for nitrite. In the 
liquid which had not been kept under toluol no nitrite was found, 
but nitrate, showing that oxidation was proceeding, doubtless due to 
the presence of bacteria. 
Experiments with Fuchsia 
The plants were cut down about an inch above the level of the 
soil, and a piece of glass quill tubing attached by means of pressure 
tubing which was securely wired to the cut stump. The liquid exuded 
into the glass tubing was collected and examined, but in this case 
no evidence could be obtained of the presence of sugars—not even 
with Molisch’s test (Plimmer(i 9 ), loc. cit. p. 193), a very sensitive 
reaction given by all sugars. 
Total residue on evaporating to dryness = 0-16 per cent. 
Organic residue 0-07 per cent. 
Inorganic ,, 0-09 ,, 
It will be seen from this that although no evidence could be 
obtained for the presence of sugars, yet there is an organic solute 
(or solutes) present in the sap. 
We have been able to throw very little light on the additional 
organic substances present in these experiments with both Vine and 
