440 
J. ARTHUR HARRIS AND JOHN V. LAWRENCE 
degrees with divisions sufficiently large to allow of reading to approxi- 
mately thousandths of degrees. Ether or carbon bisulphide vaporized 
by a dried air current in a Dewar bulb was used in determining the 
freezing point of the sap. 
In many instances a cloudiness or flocculent precipitate similar to 
that described by Gorke (1906) was observed when the sap approached 
the freezing point or passed it in undercooling. We had no facilities 
for any investigation of these substances but believe their presence 
does not greatly, if at all, influence our results. 
The results are recorded in degrees depression, A, corrected for 
undercooling, and in atmOvSpheres pressure, P, from a table published 
elsewhere (Harris and Gortner, 1914). 
We were able to make freezing point determinations on seven 
species representing three genera of Loranthaceae, parasitic upon a 
considerable number of hosts. Altogether 44 samples of parasitic 
tissue were used. In 42 cases sap was also extracted from the leaves 
of the host. 
The results, arranged primarily by the species of parasites and 
secondarily by the magnitude of the freezing point lowering, appear 
in the following protocol. For convenience of reference our field 
numbers have been retained. The values of A and P found for the 
parasite are given at the extreme right, opposite the host on which it 
was taken. Those found for the tissues of the host are placed imme- 
diately below the name of the host species. The + and — values 
given below the constants for the parasite show whether they are 
larger or smaller than those obtained from the tissue of the host, and 
the magnitude of the difference. 
III. Presentation and Analysis of Data 
I. Phoradendron flavens (Sw.) Griseb. 
538. On Guarea Swartzii DC. 
March 18. A = 0.90, P = 10.8 
528. On Guarea Swartzii DC. 
March 18. A = 1.02, P = 12.3 
A = 1.27, P = 15.3 
+ 0.37, + 4.5 
A = 1.34, P = 16.2 
-f 0.32, + 3.9 
II. Phthirusa lepidobotrys (Griseb.) Eichl. 
104. On Dodonaea jamaicensis DC. A 
Feb. 7. A = 1.09, P = 13. 1 
510. On Viburnum villosum Sw. 
March 18. A = r.15, P = 13.9 
A = 1.24, P = 14.9 
+ 0.15, + 1.8 
A = T.36, P = 16.4 
4-0.21, + 2.5 
