281 
Fuller data on the amount of water in pear, apple and 
quince are given by Penhallow! from recent determinations. 
He took branches ‘‘representing on the one hand the growth 
of two years, and on the other hand the growth of four 
years,” gathered at different seasons of the year. His re- 
sults were as follows :» 

_—— 











February. March. April. September. December. 
2 4 2 4 2 4 2 4 
years. | years. | years. | years. | years. | years. | years. | years. | years. | years. 
Pear ek 49.9 47.7 49.7 48.1 55.4 54.0 54.0 51.5 53.7 50.0 
Apple ....| 49.5 44.8 45.7 4i.5 49.0 46.4 56.2 54.5 48.3 59.0 
‘Quince....' 45.5 pO a Be ag gy PED TISAI alelates «ONS gre datolecd 56.3 Ae Oe ES es ee 

The most important part of the year for our purposes, 
May, June and July, in which the disease is most active, is 
not covered by this table. It is, however, interesting to 
note that for the time given the several percentages of 
water in the apple and quince are for the most part less 
than the corresponding ones in the pear. Averaging the 
amounts for the pear and apple (the data for the quince be- 
ing too imperfect for use) we obtain the following results : 






Averages, Pear.; Apple. 
“Lwo years’ prowth for the five months.......... 00000. 52.5 49.7 
Four years’ growth for the five months ... ............ 50.2 49.2 
mocalaverace for the five'months<«:)). ies 2.9.0. 51.4 49.4 

These figures show a difference of two per cent. of water 
in favor of the pear, which is doubtless a larger difference 
than that obtained from Emmons’ figures, because younger 
growth was taken. This is evidently true, when we look 
at the difference in the branches having four years’ growth 
which show but one per cent., while those of two years’ 
growth show nearly three per cent. difference. 
These data sufficiently demonstrate that a pear tree con- 
tains more water as a rule than an apple tree. This coin- 
cides with the fact that the pear blights more easily than 
the apple. But if these are to be laid down as correlative 
facts, it should also hold true that a Bartlett pear has more 
water than a Seckel, as there is as much difference between 
these two varieties of pears regarding their readiness to 
blight as between some varieties of pears and apples. It 
was to settle this question that the several determinations 
of the accompanying table were made. In each case the 
whole of the last period of growth was taken. <A handful 
1Amer. Naturalist, Vol. XX, 1886, p. 429. 
