76 Physico-Chemical Properties of Vegetable Saps [March, 



In this paper we present data concerning the physicochemical 

 properties of the cell sap from the tissues of the wall and the ab- 

 normal carpellary whorl" of fruits with trimerous fruit wall and 

 tetramerous: prolification. The materials comprise about 60 

 samples of this class obtained by the dissection of about 100,000 

 fruits. 



The following conditions have been found in the materials 



examined. 



The physico-chemical constants considered — specific gravity, 

 concentration, depression of the freezing point, osmotic pressure, 

 electrical conductance and mean molecular weight — are all suscep- 

 tible to the influence of the environmental and possibly to the 

 physiological state of the plant upon which they are borne. This 

 is shown by the facts (a) that the mean values of the constants 

 differ sensibly from series to series;^^ ^nd (b) that the variability 

 of the determinations within the individual cultures is, in general, 

 larger in the cases in which the collections extended over a longer 

 period of time, and in consequence comprised fruits which had 

 been developed under a wider ränge of conditions. 



The specific gravity of the sap of the fruit wall is of the order 

 1.0200, while that of the proliferous mass is distinctly lower. Con- 

 centration, i. e., weight of solutes / weight of water, is about 0.0400 

 for the wall and sensibly lower for the included mass. If the dif- 

 ferences in specific gravity of the sap from the wall and the in- 

 cluded mass be expressed in percentage ratios, with the variable 

 term {d-i) of the specific gravity of the wall as a base, the density 

 of the sap from the mass is, for the averages of the larger series, 

 5.5, 5.7 and 11.6 percent lower than that of the wall. 



The specific electrical condiictivity is of the order 0.013000 for 

 the sap of the ovary wall, and about 0.004300 lower for that ex- 

 tracted from the included carpellary whorl. In the three principal 

 series of determinations the conductivity of the sap from the in- 



11 The two parts of the abnormal fruit discussed here are the normal outer 

 wall, the wall, and the included abnormal whorl of carpels, called the prolifica- 

 tion or the included mass. 



12 Possibly these differences are in part due to differentiation in the strains 

 of plants used; two of the five series were from a source diflerent from the 

 others. 



