IN THE ANIMAL ORGANISM. 225 



ductors of mechanical effects. But the muscular 

 system is interwoven with innumerable nerves. 

 The substance of the uterus is in no respect differ- 

 ent in chemical composition from the other mus- 

 cles ; but it is not adapted to the change of matter, 

 to the production of force, and contains no organs 

 for conducting away the moving power. Cellular 

 tissue, gelatinous membranes, and mucous mem- 

 branes, are far from being destitute of the power of 

 combining with oxygen, when moisture is present ; 

 we know that, when moist, they cannot be brought 

 in contact with oxygen without undergoing a pro- 

 gressive alteration. But one surface of the intes- 

 tines and the cells of the lungs are constantly in 

 contact with oxygen ; and it is obvious that they 

 must be as rapidly altered by the chemical action of 

 the oxygen in the body as out of it, were it not 

 that there exists in the organism itself a source of 

 resistance, which completely neutralizes the action 

 of the oxygen. Among the means by which this 

 resistance is furnished we may include all sub- 

 stances which are capable of combining with oxy- 

 gen, or acquire that property under the influence 

 of the vital force, and which surpass the tissues 

 above mentioned in their power of neutralizing its 

 chemical action. 



All those constituents of the body which, in 

 themselves, do not possess, in the form of vital 

 force, the power of resisting the action of oxygen, 

 must be far better adapted for the purpose of com- 



