Miih'i- \('i\\ iicnrlv sinrrctlcd in :iii :iIIimii|iI Io foirc iliis iii-w 

 i;i'«>\\lli h) |»i'(»«lnc(' li)ii-('s ill rijilit ;iiii;l('s lo llic iioniijil dii-cct ion : 

 j. ('., llicy wci'c in;i(l<' h> ImmmI niorc llian S(( (Iciii-ccs. 



Tlic r.-nl lliiit new lild-cs cmii, if ncccssiiry, he rui-nicd ;i( sndi 

 ;i ui'cjil an^lc from llic noiinai is of very lii-cal advanta.uc lo the 

 clicslnnl in llic j)roc('ss of licalini; over scais made, for example, 

 by cutting onl diseased sj)ols in (lie Itark. As food is conveyed 

 tliroiiiili a ])laiil in very dilnte walery solnlioiis, it is necessary 

 Dial a ureal anionnt of sa|» lie eircnlaled or conveyed to a point 

 where any c(»nsidei"il>ie* anionnl of food is demanded. If the 

 tnhes which primarily convey sap slionld be severed, as when a 

 diseased spot lias been cut out of the bark, the free transfer of 

 sa]) is at most seasons of tlie year immediately reduced to a mini- 

 nnim in the severe*! or "dead ends" of t liese saj* conduct in,u 1 ubes, 

 Avliich from the point of view of circulation, now hold about 

 tlie same relation to the uninjured tubes that the staniiant arm 

 of a river does to the main river. 



So far as tlie actual food is concei-ned, it is obvious that the 

 amount of sap necessary to sujiply the re(iuisite food cannot 

 reach the upper and lower edijics of a scar by means of the dead 

 ends of the conducting tubes as readily and rai)idly as at the 

 edges where there is a continuous stream of sap jiassing along 

 the uninjured tubes. 



Oftentimes just below a broad scar which reaches to the wood, 

 and less often above it, a triangular piece of bark will die. This 

 is due directly or in<lirectly to the inability or great difficulty 

 that the sap lias in reaching these places. In order to preclude 

 the possibility of the bark dying back either above or below a 

 scar, and thus furnishing favorable shelters for insects, the top 

 and bottom of the scar should be pointed instead of allowed to 

 remain abrui)t or rounded. Under ordinary conditions it takes 

 no longer for a scar six inches long and an iiicJi wide to heal 

 over completely than it does for one an inch long and an inch 

 wide, simply because the healing over depends almost entirely 

 upon the growth at the sides of the scar. As I have already in- 

 timated, all cuts should be made with instruments that are kept 

 very sharp. 



(2). Mycelium in the wood. 



