82 CARNEGIE INSTITUTION OF WASHINGTON. 



blackened bone-marrow could be seen ever5rvvhere accurately de- 

 lineated from the surrounding structures. This method should prove 

 of value in studies of bone development, both normal and where 

 disturbances of development and growth of bone are produced experi- 

 mentally. Dr. Wislocki found that differences exist in bone-marrow 

 cells of the different mammalia as regards their ability to phagocytize 

 and store particles of carbon. In the cat and dog the phagocytosed 

 carbon is confined to the liver, spleen, and lungs; in the guinea-pig 

 the bone-marrow also takes up some of it; while in the rabbit it is 

 found distributed equally between the liver, lungs, spleen, and bone- 

 marrow. 



Cultures of Human Lymph-Glands. 



Dr. Lewis and Dr. li. T. Webster have made a series of successful 

 plasma cultures from normal and pathological lymph-nodes obtained 

 by operation at the Johns Hopkins Hospital. Autoplasma and homo- 

 plasma were used as media, the outgrowths in the two being about the 

 same, except that migration took place slightly earlier in autoplasma. 

 The investigators were able to demonstrate in this way that in tissue 

 cultures maintained at body temperature the lymphocytes of both 

 normal and pathological lymph-nodes are actively amoeboid and 

 migrate in a definite and characteristic manner for several days. 

 The establishment of this point is of considerable chnical importance, 

 in that it offers an explanation for the local accumulation of lymphoid 

 cells such as occurs in lymphatic leukaemia. Furthermore, it seems 

 probable that lympho-sarcoma is not a neoplasm, but a response on 

 the part of the lymphocytes to a localized chemotactic disease-causing 

 agent. 



The migration of the lymphocytes precedes that of the larger 

 wandering cells and giant cells, beginning within an hour or two after 

 the culture has been placed in the warm box. This migration con- 

 tinues for two or more days until all the living lymphocytes have left 

 the explant. They migrate out into the plasma clot more readily 

 than along the cover-slip and at a maximum rate of 0.03 mm. per 

 minute. The path of migration is irregular, but in general it is away 

 from the explant. The cells may be deflected from their course by 

 coming in contact with other cells or with fibrous threads. The 

 migration may be interrupted by rest periods, during which the lym- 

 phocytes assume a rounded form. While moving they are elongated, 

 with the nucleus at or near the forward-moving end. The nucleus, 

 though plastic and continually changing shape, forms the broadest 

 part of the cell. The scant amoeboid cytoplasm in front of it is homo- 

 geneous and free of granules. The bulk of the cytoplasm is behind 

 the nucleus and forms a finger-shaped process containing mitochon- 

 dria and granules. The striking polarity exhibited by the moving 

 cell may be recognized also in the more rounded resting-stage. 



