156 PHARMACEUTICAL BACTERIOLOGY 



V. Cytosis 



By cytosis is meant certain cell activities which partake of the char- 

 acter of symbioses. They may be classed into autocytoses and hetero- 

 cytoses. In the former cells derived from and forming a part of the 

 organism enter into cytotic change. In the second instance, the cytotic 

 activity takes place in cells derived from some other organism. The 

 autocytose may be divided into patrocytosis and paracytosis, as follows. 



Patrocytosis. — By patrocytosis is meant an increased activity of certain 

 body cells for the purpose of protective immunization and warding off 

 the invasion by pathogenic organisms. The best example is phagocytosis, 

 which will be more fully explained elsewhere. Even more typical are 

 the special cell activities concerned in the formation of healing tissues and 

 in regenerative growths of all kinds, in plants and in animals. Among 

 the higher animals, man in particular, the leucocytes, the lymphocytes, 

 the endothehal and epithelial cells, are chiefly engaged in the patrocytotic 

 activities. In plants the sphaerocytes which are most abundant in ripe 

 fruits, form a most important patrocytosis (sphaerocy tosis) , these struc- 

 tures being thrown off from the cytoplasm for the purpose of continuing 

 the life of the plant part after such part has become separated from the 

 mother plant. They also ward off the invasions by the organisms of 

 decomposition. The sphaerocytes do not begin to develop abundantly 

 until active cell proliferation (in cambial zone and apical areas and else- 

 where) has ceased. These structures evidently continue the life of the 

 cell, after cell division has ceased. 



In patrocytosis, certain body cells, that is cells which are normal to 

 the multicellular organism, perform a beneficient relationship with the 

 organism of which they are a part, which beneficient relationship is in every 

 way mutually helpful. The patrocytes occupy a subordinate position 

 toward the organism, but their work is to assist in the maintenance of the 

 state of health. In a way, they bear the same relationship to the organism 

 that children of a family bear to the head of the family in a well regulated 

 family. The patrocytes take their origin in the organism and they are abso- 

 lutely dependent upon the living organisms for their existence. 



Paracytosis. — This is the opposite of patrocytosis. In paracytosis 

 certain body cells assume an antagonistic relationship toward the organ- 

 ism of which they are a part and from which they took their origin. Typ- 

 ical examples are malignant growths of all kinds, such as epithelioma, 

 sarcoma, carcinoma. Here again the epithelial and endothehal cells play 

 an important part. In epithelioma we find an enormously augmented 

 pathologic proliferation of epitheUal cells. For some cause or causes 

 yet unknown the epithehal cells refuse to bear a normal relationship to 

 the rest of the body cells. They appear to have become vicious strikers. 



