THE LYMPHATIC SYSTEM. 181 



seem to be its antecedents, modifications, or derivatives, viz., 

 the extensive system of branched corpuscles in the matrix of 

 the serous membranes, whose growth and proliferation form 

 large tracts when they possess a sufficient blood-supply, and 

 between which the lymph circulates, affording a channel of 

 escape for the dischajged bits of protoplasm, their offspring ; 

 the throwing off of similar bits of protoplasm by the surface 

 endothelium of the serous membranes ; the probable transfor- 

 mation of the branched cells into fat-cells, and the conversion of a 

 branched connective- tissue cell into an endothelial cell, when it 

 reaches a free surface. Again, the fact that similar endothelial 

 cells line the blood and lymph channels, and also cover the reti- 

 culum of the lymphatic nodes and follicles, and that in the 

 latter forms, when we have also a rich capillary blood-supply 

 that is, a supply of oxygen the accumulation and probable 

 elaboration, if not proliferation, of lymphoid corpuscles goes on 

 in a more extensive manner than in the lyrnphangeal tracts ; 

 taken together, all point to the idea that they are different 

 forms of protoplasm which have been converted, or are con- 

 vertible, one into the other under proper conditions of tempera- 

 ture, food-supply, and excitability, the definite limitations of 

 which are but imperfectly known. 



In the germinating tracts, superficial and deep, of the serous 

 membranes, in the lymphatic nodes and follicles of the ali- 

 mentary canal, .and also in the lymphoid organs (spleen, ton- 

 sils, etc.), we have active farms, reproduction by budding, and 

 division. The formation of the lymphoid corpuscles, which 

 may be considered as so many amoebae sporting in a nutritious 

 fluid, and engorging themselves with that which is brought to 

 them by the agency of the absorbents and lymph-channels, 

 under conditions favorable to great activity, free to penetrate 

 most of the tissues, and, perhaps, become fixed forms. These 

 processes of activity, when confined to the limits of the organs 

 mentioned, are conducive to life and growth, but occurring in 

 the allied forms that have become fixed, as the corneal branched 

 cells, the connective-tissue cells, or the endothelial cells, to any 

 considerable extent, inaugurate the processes of disease and 

 death. Thus these comparatively indefinite and undifferen- 

 tiated forms of protoplasm may be said to be keys to life and 

 death. 



