212 R. B. HARVEY 
Table i. Freezing points of juices from tumor and healthy tissues 
Ricinus 
Leaf — 0.793° C. — 0.815° C. 
Tumor — 0.953 C. — 0.746 C. 
Stem — 0.712 C. —0.590 C. 
Daisy 
Leaf — 0.810° C. 
Tumor — 1.170 C. 
Stem — 0.783 C. 
Beet 
Leaf — 0.920° C. 
Tumor — 0.970 C. 
Root — 1. 210 C. 
In Ricinus and daisy the tumor tissue yields an expressed juice with a 
greater freezing-point depression than that of adjacent normal tissue. But 
there is more woody tissue in the normal stem than in the tumor tissue of 
the Ricinus and daisy. The author does not regard these freezing points as 
the true values for the tissue. They are given for the purpose of showing 
the errors which may arise from the method of obtaining the freezing points 
of these tissues. 
By using a thermocouple threaded through the tissue the freezing point 
can be obtained directly. The apparatus used in these determinations 
was the same as that reported in a previous paper (18). A piece of tissue 
of the same size in each case was threaded upon the thermal junction and 
cooled by ether evaporation to a desired point. Inoculation of the tissue 
was brought about by knocking it against the wall of the surrounding 
tube which was covered with frost. By this means the undercooling could 
be regulated quite accurately. When the undercooling is the same, the 
freezing points of the tumor tissue and of adjacent healthy tissue are nearly 
the same ; in any case there is only a few hundredths of a degree difference, 
as shown in table 2. 
Table 2. Freezing points of tumor and healthy tissues obtained by thermocouple 
Ricinus 
Undercooling Freezing point 
Tumor — 1.49° C. — 0.40° C. 
Healthy stem — 1-49 C. —0.41 C. 
Tumor — 2.20 C. —0.60 C. 
Healthy stem — 2.37 C. —0.64 C. 
Beet 
Tumor - 2.92° C. - 1.38° C. 
Healthy root — 2.90 C. — i-33 C. 
Tumor — 4.44 C. —1.74 C. 
Healthy root — 446 C. —1.72 C. 
