482 ' The University Science Bulletin. 



involve after many days a small area about the fragment.^^ With 

 this second coagulation the cells appear. They are in close contact 

 with the fibrin and they glide out just behind the spreading area of 

 change in the jelly like clot. This movement continues only so long 

 as the process of coagulation proceeds. The cells are elongated 

 spindles closely cemented to the fibrin, yet capable of gliding on its 

 surface. With the completion of the coagulation their movement 

 ceases. They come to rest. In this state they will remain ap- 

 parently indefinitely unless fresh fibrinogen is added. When this is 

 added they again occasion its coagulation, move into it, and again 

 come to rest when the coagulation is completed. 



The whole picture of activity in these cells is that which can be 

 readily interpreted in terms of the liberation by them of some sub- 

 stance insoluble in body fluids, but readily adsorbed or chem- 

 ically combined with fibrinogen. The combination leads to the 

 formation of fibrin. The movement and the clinging of the cell to 

 the fibrin indicates further that this substance is one which has 

 strong affinities for the cell. These cells do not crawl, but they 

 glide, and are held firmly to the fibrin. Their gliding is directly 

 proportional to the spread of the coagulant. Such can take place 

 only in presence of a substance which is strongly attracted, not only 

 by the fibrinogen, but also by the cell. Energy production in these 

 cells is centered, therefore, about this substance. How it is formed in 

 the cells becomes, then, a problem of interest. The fact that the 

 cells come to what appears to be complete rest in the coagulated 

 clot indicates that it is the product of the one reaction taking place 

 within them. 



For several years it has been evident that energy production in the 

 body is the result of chemical change. It is further recognized, as 

 Bayliss*^ clearly points out, that hydrogen and carbon enter chiefly 

 into this reaction. Nitrogen in the body is used largely for the build- 

 ing of the substratum, proteins, in which these reactions proceed. 

 This indicates that the reactions leading to protein syntheses are 

 different from those producing energy. 



What has not been shown is the nature of the products formed 

 in this energy-producing reaction. It has been thought that oxygen 

 enters directly into this reaction, and at one time it was thought 

 that the products formed were largely carbon dioxide and water. 

 Recent careful experiments have indicated that this is not true. 

 Fletcher'- has shown clearly that oxygen does not enter into the 

 contraction phase of muscle, but is adsorbed largely in the recovery 



