OSMOTIC PRESSURE IN RELATION TO PLANT DISTRIBUTION 181 



(1913) attempted to discover a connection between the 

 depressions of freezing-point, densities, and mean molecular 

 weights, of normal and abnormal fruits of Passiflora gracilis. 



The abnormalities consisted in the occurrence of ex- 

 ternal sutures and placentae in excess of the usual number. 



These authors distinguished between the effects of 

 heavy and light pressing upon the nature of the sap 

 obtained, and in other ways took care that the abnormal 

 fruits and the controls were subjected to exactly similar 

 treatment. 



As the result of the examination of twenty-three samples 

 of abnormal fruits and their controls, it was found that a 

 very small excess ^pressure and diminution in mean 

 molecular weight was found in favour of the abnormals. 

 These are shown below. 



TABLE XLVI. 



DIFFERENCES IN OSMOTIC PRESSURES OF NORMAL AND ABNORMAL 



FRUITS. 



In view, however, of the impossibility of applying the 

 same degree of pressure and of the magnitude of individual 

 variations, it does not seem that any importance whatever 

 can be attached to the results of this interesting application 

 of physico-chemical methods, and, indeed, Gortner and 

 Harris themselves recognize this fully. 



