BiRRows: Sttdy of Body Cells. 481 



As early as 1913" I had noted, however, that the movement of the 

 cell of the organism is not one which is governed necessarily by such 

 factors.^ These cells in the medium of the cultures move always 

 out and away from other cells ; and in further studies carried on over 

 several years, I have continually noted that the large number of 

 these cells show no change in contour during their movement. Their 

 movements are not amoeboid. They glide along like bodies carried 

 by some external force. 



The picture observed in these cells is not that of a highly organized 

 body, but one liberating a surface-tension-lowering substance. 

 Their movements are like those of cayenne-pepper granules dropped 

 on the surface of water. When a number of such granules are scat- 

 tered on the surface of the water they shoot apart. This moving 

 apart is the result of the liberation by them of a surface-tension- 

 lowering substance. This accumulates in greater concentration be- 

 tween the granules. These granules are pulled apart, therefore, by 

 the greater force of the water surface without.'' 



While the connective-tissue cells take the same course outward, 

 they never become completely dispersed. These cells again fail to 

 show movement on the surface or within a liquid medium, but move 

 only and show evidence of metabolism in the presence of the fibrino- 

 gen contained in the blood plasma which I had used chiefly as a 

 medium. In a liquid medium these cells round off to perfect spheres. 

 In the plasma cultures they stick tightly to the fibrin formed in the 

 coagulation of the plasma. In contact with these fibrils they spread 

 out to take various shapes. These shapes are always peculiar to the 

 surface of their contacts.^" 



Not only the character of the movement of these cells, but their 

 general effect upon the clot, further indicates that they liberate such 

 a surface-tension-lowering substance. This substance differs in its 

 physical properties from that liberated by the granules of cayenne 

 pepper, however, in that it is apparently not soluble in water, but it 

 is adsorbed or chemically combined with the fibrinogen. The cells 

 not only stick tightly to the fibrin, but they occasion its formation. 

 When a fragment of connective tissue is placed in a drop of plasma 

 it occasions first a gelation of the whole of the layer, and then later a 

 true coagulation. This gelation commences at the tissue border and 

 spreads rapidly, to invade ciuickly the whole of a large area of the 

 fluid plasma. After a considerable latent period, the coagulation, the 

 formation of fibrin and serum, commences. This true coagulation 

 again begins at the tissue border and spreads slowly outwards, to 



