REPORTS OF I.OCAL SOCIETIES. 343 



new layer being formed between the wood and bark, termed the cambium layer, 

 and tills caml)ium layer is only tlic continuation of the cells and liber that form 

 tlio frame work of the leaves. 



About the descent of the sap, botanists disagree. Mr . Lincoln, Professors 

 Grey and Wood, who have been considered the authority on botanical subjects, 

 maintain there is a regular ilow downward of tlie nutrient matter, and support 

 the tlietiry by facts, which they claim can be accounted for upon no other 

 hypothesis. Example : Girdle an exogenous tree by removing an entire ring of 

 bark, and the tree will Hourish during one season and form a new growth, 

 above the wound, but not at all below. The next season the tree will die. 

 Why? liecause the true sap cannot descend to nourisii tlie roots. Again, if a 

 ligature be bound iirmly around the body of a tree, its growth is cliecked below, 

 while the part just above the ligature, exhibits, after a year or two, a circular 

 swelling evidently caused by the interruption of the descending saj). 



On the other hand. Prof. Johnson, of the Sliefliekl Scientitic 8choul of Yale 

 College, who is equally good authority, asserts that there is no downward flow of 

 the sap, but simply a general distribution of the nutrient inatter to tlie organs 

 of growth, and this circulation takes place by what we may call permeation. 



The walls of the cells are so constructed that, notwitlistanding they are 

 entirely closed, the fluids interchange themselves, perhaps, upon the principle 

 of endosmose, or flowing in, and exosmose, or flowing out of fluids. For 

 example, two contiguous cells tcontaining fluids of different density, will 

 interciiangc their fluids until they have a common density, and this motion if 

 kept up will result in the circulation of the sap through the entire vegetable 

 fabric. 



Precisely how the action or change takes place in the leaves, perhaps, we may^ 

 not understand. It has, however, been shown by experiment , that during 

 daylight plants do take carbonic acid from the air, use the carbon, and give off 

 the oxygen, and during the night just the reverse takes place, so that during 

 the day plants render the air more pure, and better fitted to sustain animal life. 



And this is accomplished at the same time that they are assimilating the 

 crude sap to their own use, giving off the water and taking in carbon for the 

 nourishment of the plant. The true sap then commences its descent, and 

 whether it reaches the root by permeation, as has been described, or passes 

 through the cambium layer it matters but little. 



In studying the structure of the tree, we are led to exclaim, "In wisdom hast 

 Thou made them all, for who but an all wise and beneficent Being could have 

 so arranged the various cells and tissues that each should secrete its own juices 

 without interfering one with another." 



>-) 



GARDEXIXG, 



A PAPEK READ BY MRS. J. P. m'GOWAK. 



"And the Lord God planted a garden eastward in Eden, and there he put 

 the man whom he had formed," " to dress it and to keep it." 



In this day and age of the world, a spirit of inquiry and investigation pre- 

 vails, and many wise conclusions are reached. 



There are those who would have us disbelieve everything in which Ave have 

 trusted since our earliest years, and call them untruths, myths, or allegories. 



There was no such thing as the cherry tree and the little hatchet ; no Poco- 



