104 .CHAPTER 18. 



neighbouring parts. If the reader wishes to investigate thoroughly this 

 the most debatcable subject in medicine, he may consult the learned 

 works of Goodsir, Virchow, Bennett, Lister, Aitken, Paget, and others. 



Avoiding as far as possible all minute details and doubtful points, 

 now under eager discussion among medical men, the Author hopes to be 

 able to trace out intelligently, but very briefly, the broad principles and 

 views now generally entertained in regard to Inflammation, 



The Vital principle or seat of vital activity was long supposed to re- 

 side in some one organ or tissue, — in the brain as some thought, or in 

 the blood as others thought, or in the nervous system or elsewhere. It 

 was supposed that there was some one central point or organ from which 

 all motion, activity, and growth, all life in short, was generated, — that 

 each part derived its vital action from that centre, — that parts or tissues 

 in themselves, as apart from their relation to that centre, possessed no 

 power of motion, activity, growth, or development. 



These views have given way to a belief that a vital principle, a power 

 of activity, a power of selecting and adapting the various constituents of 

 the blood for its own use, a poAver of growth and development, exists 

 inherently in each tissue. 



Whether the living power of the tissue resides in its cells, as some 

 think, or in its molecules, as others think, is not necessary to discuss in 

 this place. It is a sufficiently well ascertained fact that a vital power, a 

 power of growth and multiplication, does exist in the ultimate elements 

 of each tissue. 



Except as regards the inherent vitality and power of self-action, there 

 is no great difference between the views now and those formerly enter- 

 tained as to the growth of new matter and nutrition. By the cells, as 

 is well known, the various tissues of the body are built up and nourished. 

 The blood is the food of the cells. From it in each tissue they extract 

 those special nutrient particles which are essential to their growth, mul- 

 tiplication, development, and life, — much in the same way as the cells 

 of flowers select the colouring matters which they require. 



But as regards the nature and treatment of inflammation, the belief 

 now held, that each tissue has in itself a vital power, has led to the 

 modification of many of the ideas formerly entertained as to that disease. 

 It has caused it to be regarded more as a local and specific affection than 

 as a constitutional disturbance. It has likewise enabled several of its 

 phenomena to be accounted for, which were previously inexplicable. 



328. Nature of ivjiammation. 



Irritation is the starting-point of the state known as Inflannnation. 

 From some cause or other the part falls into a state of irritation. Irri- 

 tation acting on the part, cither directly or through the medium of the 

 blood, causes it to undergo alterations as regards the composition, con- 

 stituents and aiTangement of its cells, which enable them to attract to 



