TkKK SURGERY AS A SCIENCE 



the splitting crotch, which t<> hi- .-killed 

 eye often presents a serious danger 

 which the casual observer \\<>uld never 

 suspect. It is perfectly natural for the 

 weak crotch to exist in some tree-: tin- 

 varieties most subject to this weakness 

 are the elm, the soft maples, the lin- 

 den, and the beech. It is sometime- 

 found in other varieties, but more sel- 

 dom. It may be caused by cutting back 

 the leader and forcing out the two lat- 

 eral buds when the tree- i- young. It- 



heavy winds and the i < >n-e<|ucnt admis- 

 sion of more water. All this while tin- 

 tree continues to heal on the outside, 

 making the ]>ouch more extensive. The 

 operation continues until one of the 

 branches become- too heavy to be 

 longer supported, and is tori 1 off in a 

 windstorm. The method demised by 

 Mr. Davey for the treatment of such 

 case- is most effective. It consi-ts of 

 the chain and lag-hook, with the ad- 

 dition, in serious caSCS, <>t" a double- 



THE CHAIN AND LAG-HOOK SYSTEM 

 Weak Crotches Made Secure. Maple on Estate of George 1 judcr. Jr., Greenwich. Conn. 



treatment i- complicated, and demands 

 the utmost care, e^pt-ciallv in the ad- 

 vanced stages. When the limbs have 

 attained a sufficient si/c and weight. 

 the swaying in the wind cau-es a 

 -light splitting between the diverging 

 hranclu-. Water i- thus admitted and 



starts the process f decay. Although 



the tree seeks to protect it-elf by heal- 

 ing over the out-ide of the crack, it 

 merely form- a p >urh fr the water, 

 and tlu- decay continues with increasing 

 rapidity, becau-e the tret- becomes 

 weaker by the repeated -plitting in the 



headed bolt between the branches, and 

 Ixilts through the side- of the water- 

 pouch. The chain- and lag-h >oks, are 

 1 in many ca-e- for their preventive 

 value. It i- invariably the rule where 

 tree- of thi- kind are treated, to tap 

 ihe pouch between the limbs, and pre- 

 -erve an opening by mean- of one or 

 more drain-tubes. The split itself is 

 caulked in such a manner that the bark- 

 will heal over it: however, it is some- 

 times nece-sary when the split is very 

 bad to excavate as with other cavities 

 and fill in the same manner, although 



