154 ON THE PROCESSES OF 



increased action iu both these sets of vessels ; as on exposure to cold and damp 

 temperatures ; in cases of spare and coarse diet ; or of old age. And the 

 result of this double decrease of energy is dryness, as in the former in stance, 

 but combined with leanness and corrugation of the organs that are thus 

 affected. It is hence the bones of old people are more easily broken, and the 

 skin is harsher and more wrinkled than in the middle of life ; hence the shri- 

 velled and squalid appearance of gipsies and beggars ; and hence, in a consi- 

 derable degree, the low and stinted stature of the Esquimaux, Laplanders, 

 and Tongooses. 



For all the usual purposes of health and organic nutrition, the common 

 action and common degree of action evinced by these respondent systems of 

 vessels are perfectly sufficient, though not more than sufficient. It may hap- 

 pen, however, that in consequence of severe violence from external injury or 

 internal disease, a considerable portion of an organ, as a part of seme of the 

 muscles that belong to an arm or a leg, may be totally destroyed or killed, 

 and, consequently, rendered incapable of performing its proper function. 

 How is nature, or, which is the same thing, the remedial principle of life, to 

 act in such circumstances ? If the dead part remain, it is manifest that it 

 must impede the living parts that surround it in the execution of their appro- 

 priate office : independently of which they want the space which the dead part 

 occupies, and the aid which it formerly contributed. It is obvious that two 

 processes are here necessary: the dead part must be carried off, and its post 

 must be filled up by a substitute of new matter possessing the precise proper- 

 ties of the old. And here we meet with a clear and striking instance of 

 that wonderful instinctive power which pervades every portion of the vital 

 systems, both of the animal and vegetable world, and which is perpetually 

 prompting them to a repair of whatever evils they may encounter, by the 

 most skilful and definite methods. 



In order to comply with this double demand of carrying off the dead matter, 

 and of providing a substitute of new, each of the systems before us com- 

 mences, in the living substance that immediately surrounds that which re- 

 quires removal, a new mode and a new degree of action. 



A boundary Ime is first instinctively drawn between the dead and useless, 

 and the living and active parts ; and the latter retract and separate themselves 

 from the forme? as though the two had been skilfully divided by a knife. 

 This process being completed, the mouths of the surrounding absorbent ves- 

 sels set to work with new and increased power, and drink up and carry off 

 whatever the material may be of which the dead part consists, whether fat, 

 muscle, ligament, cartilage, or bone ; the whole is equally imbibed and taken 

 away, and a hollow is produced, where the dead part existed. At the same 

 time the mouths of the corresponding secernent vessels commence a similar 

 increase and newness of action, and instead of the usual lymph, pour forth 

 into the hollow a soft, bland, creamy, and inodorous fluid which is denomi- 

 nated pus ; that progressively fills up the cavity, presses gradually against 

 the superincumbent skin, in the gentlest manner possible distends and atte- 

 nuates it, and at length bursts it open, and exposes the whole of the interior to 

 the action of the gases of the atmosphere. 



It was at one time conceived, and by writers of considerable eminence and 

 judgment, and of as late a date as the time of Mr. Hewson, that the injured 

 and dead parts were themselves dissolved and converted into pus ; but this 

 opinion has been disproved in the most satisfactory mariner by the minute 

 and accurate experiments of Mr. John Hunter, Sir Everard Home, and Mr. 

 Cruickshank ; and the process has been completely established as I have now 

 related it. 



In what immediate way the gases of the atmosphere operate so as to assist 

 the secernent mouths of what is now the clean and exposed surface of a 

 wound, in producing incarnation, or the formation of new matter of the very 

 same kind and power as that which has been carried off, and enable them to fill 

 up the cavity with such new matter, and perfect the cure, we do not exactly 

 know. Various theories have been offered upon this very curious subject 



