HORTICULTURAL JOURNAL. 237 



have reason to believe that it will be equally fine ; and, if so, it will attract 

 a great deal of attention. 



We thus find that the Philadelphia Agricultural Society, the Horticul- 

 tural, the Poultry and Bird Fancier's Societies, are now actively co-operating 

 in the common effort to render the State Fair worthy of the capabilities and 

 reputation of the city. As regards the Franklin Institute, we have as yet 

 been informed of no definite action by that organization in reference to its 

 fall exhibition, but as its members are generally sensible, public spirited, 

 and much interested in the welfare of Philadelphia, we feel assured they too 

 will wisely resolve to make their usual display in conjunction with the State 

 Agricultual Society. So thinking, we look confidently for their energetic 

 assistance in getting up a magnificent industrial demonstration. — JST. Amer. 



ON THE MOTION AND COMPOSITION OF SAP IN PLANTS, 



BY WALTER ELDER. 



Sap is the vital essence of plants, the essential agent of vegetation, and 

 the active agent of growth. It is present in a dormant state in the seed, 

 the dry bulb, and in deciduous plants in winter, and only needs the combi- 

 nation of heat and moisture to set it in motion. 



Its composition is very different in different plants, which is perceptible 

 in their earliness and lateness, their tenderness and hardiness, their ligneous 

 or herbaceous natures, and in the different degrees of heat and moisture at 

 which vegetation commences in different specie3. We see some luxuriating 

 in swamps and others flourishing on mountain tops ; some thriving in the 

 sunshine, others delighting in the shade ; some evergreen, others deciduous ; 

 some vegetating three fourths, others dormant two-thirds of the year. Some 

 are consumed by "Dry rot" produced by moisture, others suffer from the 

 same disease produced by dryness. 



Its motion is also different in different plants ; this is visible in the rapidity 

 or slowness of growth. The too common expressions the "rise of sap" in 

 spring, and the "return of sap" in the fall have created many erroneous 

 impressions especially in young minds. I have met with men who made 

 great pretensions to arboreal knowledge, say with much confidence that the 

 "whole vital essence or life of the trees was in the roots during winter." 



Now the least consideration would convince any one that such is an error. 

 The truth is, that the tree is more densely filled with sap in winter, than at 



