io6 
OTIS F. CURTIS 
tissue having the higher concentration will withdraw water from the other, 
causing the latter to wither. He demonstrated that leaves may withdraw 
water from fruits, or that a tomato plant having a high sugar content, if 
grafted to one with a lower sugar content, may withdraw water from the 
latter, causing it to wither. 
In order to determine whether ringing and defoliation have any effect 
on the concentration of the sap, the freezing points of the sap from some of 
the stems of Philadelphus, previously described in table 2, were determined. 
The shoots were in pairs, as shown in figure i , and for each determination 
both stems of the pair were used. As soon as possible after cutting the 
shoots, the leaves were removed and the stems were immediately cut into 
Fig. I. Effects of ringing on leafy and defoliated shoots of Philadelphus. 
1. Not ringed, leaves remaining. 
2. Ringed, leaves remaining. 
3. Not ringed, leaves removed. 
4. Ringed, leaves removed. 
Black strings tied at x indicate the original length of the shoots. 
short pieces and placed in large test tubes which were then quickly plunged 
into a freezing mixture. After the tissues were thoroughly frozen they were 
ground in a mortar and the freezing point of the pulpy mass was determined. 
The material from each of numbers i, 3, and 4 was extracted in 80 percent 
alcohol and this extract was hydrolyzed and analyzed for reducing sugars. 
The total sugar found, expressed as invert sugar, is recorded with the other 
