BEHAVIOR OF TISSUE-CELLS A\D FOUMATIOX OF GLiNT-CELLS 273 



of k'lR'ocytcs within tlu' central necrotic areas.) (e) The formation 

 of cheuiotactic .substances may cease because the substance causing? the 

 iutlannuation has been used up, or because the bacteria have been 

 destroyed, or from an}^ of the causes that terminate inflammation. 

 Those leucocytes still advancinor will reach a point wh(!re there is as 

 much chemotactic substance behind as in front — they will then stop 

 advancing.'" As the fluids exuded in the central portion continue to 

 dilute the chemotactic substances and wash them out, there will soon 

 be less chemotactic substance in the center of the inflamed area than 

 there is farther out, hence the leucocytes M'ill move away from the 

 center toward the periphery, following the chemotactic substances back 

 into the blood-vessel and the lymph-stream. These are the conditions 

 that exist at the close of the inflammatory process, which results in the 

 dispersion of the leucocytes. 



General leucocytosis can be explained equally well on the same 

 grounds. Chemotactic substances from the area of inflammation enter 

 the blood-stream, and so, in a very dilute form, pass through the bone- 

 marrow. The cliemotaxis in the blood will be greater than that of 

 the marrow, and the leucocytes will move toward and into the blood. 

 As long as the blood contains more chemotactic substances than the 

 marrow, leucocytosis will increase, to stop when the amount in blood 

 and marrow is alike or when there is less in the blood than in the 

 marrow. 



Behavior of Tissue=cells and Formation of Qiant=cells. — The 

 free cells of the tissues involved in inflammation can, of course, obey 

 the same influences as the leucocytes, and apparently do so in so far 

 as they are not cheeked by structural impediments to flowing motion ; 

 1. e., the more closely a cell is related to a single drop of fluid pro- 

 toplasm, the more closely does it resemble in the simplicity of its 

 reactions the /'artificial ameba." An illustration of the cliemotaxis 

 of epithelial cells is furnished by B. Fischer,"" who found that stained 

 fats cause growth and migration of epithelial cells in the direction of 

 the fat. Cells with much cytoplasm are best fitted to move freely, as 

 a rule, and hence we see chiefly the large endothelial cells of the lymph 

 sinuses and the serous cavities, and the large hyaline and granular 

 ••ells of the blood acting as phagocytes, for phagocytosis is no difi'erent 

 from ameboid motion which continues about a particle until it is sur- 

 rounded; likewise we see the "epithelioid" and large endothelial cells 

 with their abundant cytoplasm fusing together to foinn giant-cells. 

 (Note that such giant-cells are formed particularly in conditions in 

 which the epithelioid cell is more abundant than is the leucocyte, 

 e. g., tuberculosis and other chronic inflammations. The cells that 



59 The phagocytic action of leucocytes in vitro is decreased bv substances tliat 

 lower the surface tension, e. g. chloroform (Hamburger, K. Akad. Wetensch., 1911 

 (XIII (2)), 802). Ethor-solu])le substances from bacteria have no effect on 

 phagocytosis (IMiiller, Zeit. Immunitiit., 1908 (I), 61). 



GoMiinch. med. Woch., 1906 (53), 2041. 

 18 



