446 J. ARTHUR HARRIS AND JOHN V. LAWRENCE 
Phoradendron flavens, 2 determinations 
For parasite A = 1.305, P = 15.75 
For host A = 0.960, P = 11.55 
Difference + 0.345 + 4.20 
Phthirusa lepidohotrys^ 5 determinations 
For parasite A = 1.400, P = 16.84 
For host A = 1.134, P = 13.64 
Difference + 0.266 + 3.20 
Phthirusa parvifolia, 13 determinations 
For parasite A = 1.347, P — 16.19 
For host A = I. no, P = 13.38 
Difference +0.237 + 2.81 
Phthirusa pauciflora, 2 determinations 
For parasite A = 1.650, P = 19.85 
For host A = 1.720, P = 20.65 
Difference —0.070 — 0.80 
Dendrophthora cupressoides, 9 determinations 
For parasite A = 1.177, P = 14.16 
For host. A = 1.048, P = 12.62 
Difference +0.129 + 1.54 
Dendrophthora gracilis, 8 determinations _ _ 
For parasite A = 1.176, P = 14.15 
For host A = 1.098, P = 13.24 
Difference +0.078 + 0.91 
Dendrophthora opuntioides, 3 determinations. _ _ 
For parasite A = 1.153, P = 13.86 
For host A = 1.246, P = 14.96 
Difference —0.093 — 1. 10 
The first point to be brought out by these averages is that the 
osmotic pressure of the tissue fluids of the leafless species is distinctly 
lower than that of the juices extracted from the leaf-bearing forms. 
The mean depressions in the former are 1.153°, 1.176° and 1.177°, a^s 
compared with 1.305°, i-.347°, 1.400°, and 1.650° in the latter. 
The second is the emphasis laid upon the higher osmotic pressure 
of the fluids of the parasite as compared with those of the host. 
In five of the seven comparisons the mean osmotic pressure of the 
juices of the parasite is higher than that of the leaf tissue of its hosts. 
The two exceptions are represented by only 2 and 3 determinations 
