52 REPORT — 1842. 



The whole life of animals consists of a conflict between chemical forces 

 and the vital power. In the normal state of the body of an adult both stand 

 in equilibrium ; that is, there is an equilibrium between the manifestations of 

 the causes of waste and the causes of supply. Every mechanical or chemical 

 agency which disturbs the restoration of this equilibrium is a cause of disease. 

 Disease occurs when the resistance offered by the vital force is weaker than 

 the acting cause of disturbance. 



Death is that condition in which chemical or mechanical powers gain the 

 ascendency, and all resistance on the part of the vital force ceases. This re- 

 sistance never entirely departs from living tissues during life. Every abnormal 

 -condition of supply or waste may be called disease. 



But it is evident that one and the same cause of disease, that is, of disturb- 

 ance, will have different effects according to the period of life. A cause of 

 disease added to the cause of waste, may in old age annihilate the resistance 

 of the vital power, or, in other words, occasion death ; while in the adult 

 state it may produce only a disproportion between supply and waste, and in 

 infancy only an abstract state of health, i.e. an equilibrium between supply and 

 waste. 



Now from what has preceded, it is obvious that a deficiency of resistance 

 in a living part to the cause of waste is in fact a deficiency of resistance to 

 the action of the oxygen of the atmosphere. Professor Liebig has shown, 

 in that part of the report which I have omitted, that the phaenomena of mo- 

 tion are dependent upon the change of matter ; consequently, if by a diseased 

 transformation of living tissues a greater amount of force be generated than 

 is necessary for the production of the normal motions, it is seen in an acce- 

 leration of the involuntary motions, as well as in a higher temperature of 

 the diseased part. 



This condition is called Fever. 



And when a great excess of force is produced by change of matter, the 

 force, since it can only be consumed by motion, extends itself to the appara- 

 tus of voluntary motion. 



This state is called a Febrile Paroxys. 



Should there be any products formed during disease, which the organs in 

 their immediate vicinity cannot employ in their own vital functions, erema- 

 causis will ensue, which may be communicated to other parts of the body. 

 The physician sometimes removes those diseased conditions by exciting an 

 artificial diseased state in their vicinity, such as by blisters or by setons. In 

 this case he throws a less important part of the body into a state in which it 

 more readily yields to the oxygen, and therefore removes the causes of waste 

 from the diseased organ. When this cause of waste is reduced, the resistance 

 or vital force increases, and renovates the part removed by oxygen. 



In cases of a different kind, where artificial external disturbance produces 

 no effect, the physician adopts other indirect methods to exalt the resistance 

 offered by the vital force. He diminishes the number of blood-carriers (the 

 globules), and by this means the cause of change. He excludes from the 

 food all matter capable of conversion into blood, and gives chiefly or entirely 

 non-azotized food, which supports the respiratory process. 



In regard to the nature of the vital force, it is plain that it must be con- 

 nected with other physical forces, for its manifestations are similar; it is de- 

 void of consciousness or volition, and is, as we know, subject to the action of 

 a blister. 



Perhaps we cannot give a better notion of the Professor's theory than by 

 comparing the human body to a self-regulating steam-engine. 



Every one knows that the tube which conveys the steam to the cylinder, 



