91 



75° in the shade and 85° in the sun. But on the 7th of 

 Iklarch it was only 10° above through the day, and oa 

 ihe 18th, only 4° above at sunrise. In his opinion the sudden 

 freezing and thawing of the sap-vessels had done the injury. 

 The fluids in plants are always in motion, according to 

 Lindley; and Biot has, in fact, shown means for measuring 

 the rate of motion in the sap at all seasons. 



A. W. Dodge, of Hamilton, dissented somewhat from the 

 ~views of Mr. Ives and favored the idea that the sap descended 

 : from the branches toward the root in winter. 



C. M. Teacy, of Lynn, explained the prevalent theory of 

 botanists, as to the course of vegetable fluids. We use the 

 term sap rather loosely. The water and chemical solutions 



"taken up by the roots form a very crude fluid which rises in 

 new wood as far as the leaves, and this is one sort of sap. 

 The sweet sap of the Maple, and the equally sweet and 

 viscid sap of the Hickory, with the " sliver" of the Pine and 

 other trees, is altogether another thing, elaborated by the 

 leaves and distributed through the plant to produce its 

 growth and increase. In winter there are no leaves and 

 none of this sap is formed, the store of the preceding season 

 moves slowly over the plant, however, and toward spring 

 Tery rapidly. These two fluids are indifferently called sap, 



.^nd this leads to misunderstanding. 



Mr. Dodge continued. It was certain that the elements 

 were taken up by the roots which nourished the growth, for 

 the action of manures could not be otherwise explained, and 

 hence the roots are as much nourishing organs as the leaves ; 

 indeed they are indispensable, since by them only could the 

 plant communicate with the soil. 



Mr. Tracy replied that many plants habitually flourished 

 and matured seed with no connection with the soil. This 



