GRAFTING 431 



The difficulties in the way of blood-vessel anastomo- 

 sis have been overcome, but the physiologico-chemical 

 difficulties remain, and when these experimental trans- 

 plantations are carefully scrutinized it is found that 

 sooner or later the experiment animal is apt to die 

 because of some condition referable to them. This 

 is well exemplified in the transplantation of a cat's 

 kidney by Carrel and Guthrie. One kidney of a healthy 

 cat was removed and replaced by the healthy kidney of 

 another cat. The animal recovered perfectly from the 

 operation and lived about a year, when her previously 

 undisturbed kidney was removed. After this operation 

 she died in a few days with the usual symptoms of renal 

 insufficiency. Upon examination with the microscope it 

 was found that the ingrafted kidney had suffered histo- 

 logical changes that made it unable to functionate. 

 It is also exemplified in Carrel's case of successful trans- 

 plantation of both kidneys of a cat where it was subse- 

 quently found that the aorta and blood vessels had 

 undergone an extraordinary calcification unlike any- 

 thing previously known to take place in cats, and in some 

 way directly or indirectly referable to the changed 

 physiological conditions associated with, or following 

 the operation. 



It is not uncommon for a person to donate a sound 

 front tooth to another whose tooth is extracted as 

 worthless. Such a sound tooth may be implanted in 

 lieu of that lost, grows fast, and. remains useful for a 

 long time. Here, however, the conditions are somewhat 

 different, for the tooth implanted, though it remains in 

 place and is firmly attached and functionally useful, is 

 commonly a dead tooth and would quickly slough away 

 if it were soft tissue. What applies to the recently ex- 

 tracted tooth applies equally to teeth extracted long be- 

 fore or to teeth soaked in antiseptic solutions or to bits 

 of ivory fashioned into resemblance to teeth or to artifi- 

 cial teeth made of bone. All such grow fast and remain 

 useful for considerable lengths of time, according to their 



