70 PROPERTIES OF THE BL001). 



After a blow or contusion, the blood now and then bursts 

 from the vessels into the cellular membrane, sometimes form- 

 ing an ecchymosis, and sometimes a tumour, and it is a question 

 with some, whether such blood coagulates or not ; but that it 

 coagulates in most of these cases, is proved by opening such 

 tumours. Yet it has likewise been observed, that now and 

 then these tumours have been attended with a fluctuation, and 

 that, after some time, their contents have been absorbed, and 

 it has also been found that, upon opening some of them, even 

 several weeks after the accident, the blood was fluid. In such 

 cases the blood had probably undergone a change similar to 

 what was observed to take place in some of the preceding 

 experiments, that is the lymph had been deprived of its pro- 

 perty of coagulating (xxxiv), in passing from the blood-vessels 

 into the tumour : a circumstance, which, how remarkable soever 

 it may appear, agrees with what we have above observed of the 

 lymph, whose properties seemed to vary with -the state of the 

 blood-vessels (see Note xxiv). 



(xxxiv.) Extravasated blood, which has long remained fluid in a 

 bruised part, may yet coagulate when let out (see Note x). 



