496 ON THE INTERDEPENDENCE OF SCIENCE 



An external wound of the soft parts might be healed in one of two ways. 

 If its surfaces were clean cut and could be brought into accurate apposition, 

 it might unite rapidly and painlessly ' by the first intention '. This, however, 

 was exceptional. Too often the surgeon's efforts to obtain primary union were 

 frustrated : the wound inflamed and the retentive stitches had to be removed, 

 allowing it to gape ; and then, as if it had been left open from the first, healing 

 had to be effected in the other way, which it is necessary for me briefly to describe. 

 An exposed raw surface became covered in the first instance with a layer of 

 clotted blood or certain of its constituents, which invariably putrefied ; and 

 the irritation of the sensitive tissues by the putrid products appeared to me to 

 account sufficiently for the inflammation which always occurred in and around 

 an open wound during the three or four days which elapsed before what were 

 termed ' granulations ' had been produced. These constituted a coarsely 

 granular coating of very imperfect or embryonic structure, destitute of sensory 

 nerves and prone to throw off matter or pus, rather than absorb, as freshly divided 

 tissues do, the products of putrefaction. The granulations thus formed a beau- 

 tiful living plaster, which protected the sensitive parts beneath from irritation, 

 and the system generally from poisoning and consequent febrile disturbance. 

 The granulations had other useful properties, of which I may mention their 

 tendency to shrink as they grew, thus gradually reducing the dimensions of 

 the sore. Meanwhile, another cause of its diminution was in operation. The 

 cells of the epidermis or scarf-skin of the cutaneous margins were perpetually 

 producing a crop of young cells of similar nature, which gradually spread over 

 the granulations till they covered them entirely, and a complete cicatrix or 

 scar was the result. Such was the other mode of healing, that by granulation 

 and cicatrization ; a process which, when it proceeded unchecked to its com- 

 pletion, commanded our profound admiration. It was, however, essentially 

 tedious compared with primary union, while, as we have seen, it was always 

 preceded by more or less inflammation and fever, sometimes very serious in 

 their effects. It was also liable to unforeseen interruptions. The sore might 

 become larger instead of smaller, cicatrization giving place to ulceration in one 

 of its various forms, or even to the frightful destruction of tissue which, 

 from the circumstance that it was most frequently met with in hospitals, was 

 termed hospital gangrene. Other serious and often fatal complications might 

 arise, which the surgeon could only regard as untoward accidents, and over which 

 he had no efficient control. 



It will be readily understood from the above description that the inflam- 

 mation which so often frustrated the surgeon's endeavours after primary union 

 was in my opinion essentially due to decomposition of blood within the wound. 



