266 
Journal of Agricultural Research 
Vol. VII, No. 6 
32. Seedling (26694).. .A=i.o9, P= 13.2, F=30.04° 
Originated at Marco, Fla. Budded tree. * 
33. Seedling. A=i.o 9, P—13.1, P=3o.o4° 
Grown from seed of unknown origin. 
34. Butler (26690). . A=i.io, P= 13.3* F—30.02 0 
Originated at St. Petersburg, Fla. Budded tree. 
35. Seedling (26691).A=i.i5, P«i3-9, F=*29.93 0 
Originated at Buena Vista, Fla. Budded tree. 
36. Mitchell (18120).A=»i.i9, P—14.3, F=29.86° 
Originated at Bayamon, Porto Rico. Budded tree. 
37. Seedling (26713). A=*i. 23, P«i4.8, F—29.79 0 
Originated at Cocoanut Grove, Fla. Budded tree. 
38. Seedling (19379). A=»i.23, P= 14.8, F= 29.79 0 
Grown from a seed received from Hawaii. 
39. Pollock.... .A==i,24, P=14.9, F=®29.77° 
Originated at Miami, Fla. Budded tree. 
DISCUSSION OF CONSTANTS 
All these types show considerable variation in freezing-point lowering. 
For the whole series the range is from A=o.96° to A=i.43°, or 0.47 0 . 
On the Fahrenheit scale the range in the freezing point of the sap is 
from 29.43 0 to 30.27°. This variation is doubtless due to many causes. 
In addition to errors of sampling in the collection of the leaves from the 
individual trees and the unavoidable errors of measurement involved in 
the manipulation of the sap samples, there are the fluctuations attrib¬ 
utable to the uncontrollable differences in the physiological states of the 
different trees at the time of collecting the materials. 
In view of these various factors, one would not expect to find transi¬ 
tion types entirely wanting, unless the differentiation of the types be 
very clearly marked indeed. For more convenient comparison the values 
obtained from the trees of the three types may be serially arranged in 
intervals of five-hundredths of a degree (Table I). 
Tabi.3 I .—Comparison of the freezing-point lowering values of three types of Persea 
americana 
