34 GORTNER AND HARRIS: FRUITS OF PASSIFLORA GRACILIS 
DISCUSSION AND CONCLUSIONS 
From the determination of the depression of the freezing 
point, the specific gravity, and the total solids in the expressed 
juice of 23 samples of abnormal fruits of Passiflora gracilis and 
a like number of controls, we are led to the following conclusions: 
Our experiments indicate that the juice of abnormal fruits 
has a higher osmotic pressure (greater depression of the freezing 
point) than that of normals. This is true whether the abnormality 
be a meristic variation in the fruit wall—i. e. an increase in the 
number of external sutures or of the number of placentae over the 
normal condition—or the production of an entirely new structure 
in the form of an included whorl or whorls of accessory carpels 
springing from the floor of the fruit (prolification of the fruit).* 
The average molecular weight of the substances in solution 
in the plant sap is, apparently, lower in the abnormal fruits, but 
this is less consistently true for the various classes of structural 
aberrations recognized. 
While the findings are fairly consistent throughout, it must be 
remembered that the problem is surrounded with many difficulties. 
We have no desire to be dogmatic concerning these conclusions, 
realizing that a wider series of material than we could possibly 
obtain is desirable,t and that many questions remain to be in- 
vestigated.{ Furthermore, it is clear that the whole problem of 
the nature of the relationship between the structure of the fruits 
and the properties of the juice remains to be worked out. We only 
claim to have demonstrated that the physico-chemical properties 
of the plant sap deserve consideration as a first step in the 
analysis of the factors involved in morphological variations of the 
fruit. 
STATION FOR EXPERIMENTAL EVOLUTION, 
CARNEGIE INSTITUTION OF WASHINGTON, 
* In € forthoctaing meee on the morphology of normal and teratological fruits 
of Passiflora gracilis one of us will show that the oe cf prolification is to 
some degree correlated with abnormalities of the ovary wal 
We hope another year to obtain a strain of plants vias a higher percentage 
of abnormalities or at least to obtain far larger series of dissections 
{t In particular it will be of great interest to work out in detail the relationship 
Dewees the properties of the juice of the ovary wall and that of the contained 
in the case of fruits showing prolifications. Some beginning has been made 
carpe 
on this —— but as yet our data are too few to justify the discussion of this and 
several oth 
