^04 



Scientific Proceedings, Royal DubUn Society. 



the leaves later in the season, or possibly the lower temperature at wliich 

 the gatliered leaves and saps were kept. These later results are summarized 

 in the following tables : — 



Tabi,e XX. 



Syringa vulgaris : leaves. 



Here the change in pressure is very small; but the sap in the cells has 

 increased in osmotic pressure somewiiat more than the pressed sap in the 

 test-tube. We may explain tlie smaller rise in No. 67 — the pressed sap — as 

 almost entirely due to the inversion of cane-sugar, which, at the same time, 

 caused a depression of mean molecular weight. In No. 68 the stored starch 

 in the uninjured cells furnished a supply of maltose, which not only 

 augmented the increase of osmotic pressure, but, at the same time, raised 

 the mean molecular weight. 



Table XXI. 



Syringa vulgaris : -leaves. 



Here the unhltered sap, presumably sap containing starch, altered more 

 than the filtered sap ; and the observations thus fall into line with those in 

 Table XX. But the obvious explanation just given requires modification 

 before it will apply to experiments set out in Table XXII. In these, two 

 lots were made from opposite halves of leaves of one sample. From lot a 



