VITALITY AND LONGEVITY IN FRUIT TREES. 



133 



cending current could not have been con- 

 tracted more than in the ratio of four to 

 three; and, considering the diminution of 

 the heart wood, probably vvas not at that 

 point contracted at all. The necessary me- 

 chanical result is plain. The tree in a rich 

 soil poured a full current of sap into the top 

 and leaf, while every year its relative re- 

 turn surface was continually diminishing, 

 and all the return sap which at the time of 

 measurement flowed over seventeen inch- 

 es of surface was, at the crotch of the tree, 

 suddenly compressed into a surface of nine 

 inches in circumference ; and through this 

 compressed surface it was compelled to 

 run full five feet in the hot sun, before 

 reaching the root, without being refreshed 

 by the new and fresh sap from a single 

 side shoot. Of course, all the vessels in 

 the bark of the trunk were filled constantly 

 with the necessary pressure from above, 

 with more sap than they could safely re- 

 turn to the root or deposit on the trunk, 

 and were attempting to relieve themselves 

 by throwing out side shoots. This not 

 being allowed, they were gorged more and 

 more as the leaf and top increased, until 

 either organic ruptures — as in the case of 

 the cherry tree — or the chemical action of 

 the hot sun upon the gorged and impeded 

 sap — as in the case of the pear — completed 

 the catastrophe of obvious disease or death. 

 I have just now measured the pear tree 

 alluded to above, and find, since it has had 

 its own way, that the relations of the su- 

 perficies at the crotch, which is now lower 

 down, have changed from the ratio of seven- 

 teen to nine to the present ratio of twelve 

 to eighteen, — showing that the increase be- 

 tween the times of admeasurement to have 

 been three inches on the stem to one inch 

 on the branches above. The trunk of the 

 tree is also now entirely screened from the 

 hot sun by the side branches it has thrown 



out; and the sap in the stem is frequently 

 refreshed by the return sap from these side 

 branches. There is no appearance of paraly- 

 sis in the growth of the top, nor of gorged 

 sap in the stem, fermenting in the hot sun, 

 and spreading signs of disease on its outer 

 bark, or diflTusing them throughout the 

 whole trunk and top of the tree. In a 

 word, the tree has returned, or is at least 

 fast returning, to a vigorous, natural, and 

 therefore healthful condition. But afier 

 all, as it was originally made from a vicious 

 grafted sprout, instead of a healthy seed- 

 ling root, it will probably, in spite of all 

 other cure, die prematurely. Had I time 

 to write, or could I suppose that you have 

 room to publish details of this sort, I could 

 give them to any extent. 



In this country, the blotch on the large 

 limbs and trunk of the pear and apple tree, 

 in what is called the blight, is always on 

 the western side, generally southwest, or 

 facing the sun at the hour of extreme heat. 

 And wherever I have found it on the north- 

 west side, it has always been near the 

 ground ; and, on further and closer inspec- 

 tion, 1 have found in such cases that the 

 orain of the tree, wound — as it is called — as 

 it descended, toward the north; and that 

 the injury, after all, was evidently done on 

 the southwest side of the tree, at some dis- 

 tance above the ground ; and the scalded 

 and vicious sap there produced, settled with 

 the grain of the tree, by an obvious law, 

 round and down to the northwest side 

 where, like other dead matter, it accumu- 

 lated to poison the bark, or to freeze and 

 peal it from the trunk the next winter. 



It is obvious how rich soil or high cul- 

 ture, with the plough or with manure, or 

 excess of moisture, would materially and 

 necessarily increase these dangers and evils 

 by increasing the plethora and stagnation 

 in the return sap ; and if sudden cold is the 



