Mar., 1923] 
BARTHOLOMEW — INTERNAL DECLINE 
119 
sive, 13 percent in November, and about 3 percent from December to 
February inclusive. 
The month of the year in which fruits are set determines to a certain 
extent whether they will soon drop off or will remain on the tree till they 
mature. The results of the experiment as carried on in these three groves 
indicate that, at least under climatic conditions such as prevailed in this 
region from June 9, 1920, to August 9, 1921, fruits set in April, May, and 
June have the best chance, of reaching maturity. Climatic and soil con¬ 
ditions and the time of year at which fruits are set are important factors 
in determining whether or not they will remain on the trees till mature. 
This is shown by the fact that of some of the lots, of 200 lemons tagged, 
practically 100 percent remained on the trees, while of some of the other 
lots as much as 50 or 60 percent, and in one or two cases even 90 percent, 
fell off before they were more than 2 months old. That the mortality is 
often very high is indicated perhaps more strikingly by Reed’s (6) work, 
which shows that out of-4,440 flower buds, 51.98 percent set fruits, 21.71 
percent reached a diameter of inch, and only 6.62 percent reached ma¬ 
turity. 
It was found that the growth rate of individual lemons is influenced 
not only by soil and climatic conditions and the time of the year when set, 
but also by the location on the tree. While the height on the tree and the 
location, whether within the foliage or exposed on the outside, appeared to 
have an influence, the most important factor seemed to be the condition 
of the branch on which the fruit was borne. While this is true also for 
deciduous fruits, it appears to be more marked in the case of lemons. This 
variation is probably due to differences in the amounts of water and food 
substances carried by the different branches. It was found, for example, 
that some of the fruits set in April were ready to be picked in the following 
October and November, a period of 7 and 8 months after being set, while 
other lemons on the same tree were not up to picking size for at least 14 
months after being set. 
It is impossible to present here all the interesting data obtained in these 
experiments on growth rate, water content, and acidity of lemons. The 
figures given in table 1 are a summary of the data obtained in one of the 
series in the grove at Corona. This is a fair example of all the data secured 
in all the series. The lemons in this series were first measured and tagged 
August 8, 1920. The average diameter when tagged was r.15 cm. 
It will be seen by reference to table 1 that the growth rate of the lemons 
was fairly constant from August 8 to February 10, during which period the 
lemons increased in size from 1.15 to 4.60 cm. However, on the date of the 
next measurement, March 9, the average size of the lemons had decreased 
from 4.60 to 4.53 cm. Further observation will show that another slight 
decrease took place from June 9 to July 8. A glance at the figures in the 
columns headed ‘ ‘ water content” will show that at the time of this last 
