DEPARTMENT OF EMBRYOLOGY. 83 



In connection with their observations on the migration of lym- 

 phocytes, Lewis and Webster noted in these cultures the presence of 

 large giant cells closely resembling those found in tuberculous nodes. 

 They appeared to form within the explant and to migrate out into 

 the plasma clot afterward. In structure and appearance they were 

 practically identical with the large wandering cells that were present 

 in great abundance in nearly all of the cultures, differing only in their 

 larger size and greater number of nuclei. They usually appeared 

 about the second or third day, after the lymphocytes, polymorpho- 

 nuclear leucocytes, and wandering cells had left the explant. They 

 migrated out from explants from normal and tuberculous nodes, 

 nodes from acute and chronic lymphadenitis, from Hodgkin's disease, 

 and from a metastatic sarcoma. They were most abundant, however, 

 in cultures from tuberculous nodes. These giant cells were conspic- 

 uous for their large accumulation of bright-green fat globules and for 

 their numerous nuclei, which ranged in number from 2 to 60, the usual 

 number being 10 to 20. Their movements were slow and deliberate, 

 but there was some shifting, both of the cells themselves and of the 

 nuclei. When flattened out on the cover-glass, each cell was seen to 

 contain a central granular area which stained avidly with neutral red 

 in the culture and with eosin in the fixed material. Since neutral red 

 is probably taken up only by the non-living cytoplasmic inclusions, 

 this central area must be considered as non-living, probably partly 

 digested food and waste products, or perhaps segregated foreign 

 substances. 



Surrounding this central area there was a zone of fat-globules in 

 which were embedded the nuclei. Scattered about this zone, or 

 mingling with the peripheral fat-globules, were the thread-like mito- 

 chondria, the whole being surrounded by a clear, more or less homo- 

 geneous ectoplasm. Within the central area there could sometimes 

 be observed what appeared to be a centrosphere, but no centriole 

 could be made out in any of the cells, in either the living or fixed 

 material. The nuclei exhibited a peculiar and significant horseshoe- 

 like arrangement about the equator of the central area, which can 

 be best explained on the hypothesis that giant ceils arise from large 

 wandering cells by amitotic division of the nuclei without division 

 of the cytoplasm. Only one clear case was seen, however, of amitotic 

 nuclear division. On the other hand, there was no evidence that 

 these giant cells arise by fusion of large mononuclear cells. 



Effect of Potassium Permanganate on Mesenchyme Cells. 



It has been found by Dr. Lewis that, by using the strong oxidizing 

 reagent potassium permanganate, certain reactions can be produced in 

 mesenchyme cells of tissue-cultures which closely resemble some of the 

 features of mitosis, and apparently the two processes have something 

 in common. Weak solutions (1 : 40,000 and 1 : 80,000) of the reagent 



