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giant cell, believe that the latter constricts off or separates into 

 smaller marrow cells. From this standpoint, the function of 

 the large nucleated giant cell is simply that it forms one stage 

 in a peculiar method of development of the lymphoid cells of 

 the marrow. Lowit (6) speaks of the giant cell — including 

 both varieties — as having some connection with the degenera- 

 tive changes of the leucocytes, though as far as I know the 

 exact nature of the relationship is not described. He gives 

 three reasons for this view. i. They are less frequent in the 

 embryo than in the marrow of the adult, and the younger the 

 embryo, the fewer the number found in the liver and spleen. 

 The first part of the statement I cannot corroborate, as in the 

 embryo liver, especially when at the maximum of its haemato- 

 poietic activity, the giant cells (megakaryocytes) are quite as 

 numerous as in the adult marrow. The second portion of the 

 statement is true to a certain extent. The number of giant 

 cells (megakaryocytes) varies directly with the blood-forming 

 activity of the organ, so that they are not numerous in the 

 liver at its first formation nor toward the end of foetal life. 

 2, He has never been able to find them in the lymph glands, 

 even after severe bleeding. In this, Lowit is confirmed by a 

 number of other observers who have stated their inability to 

 find giant cells in the lymph glands. Indeed, this assertion 

 may be accepted as satisfactorily demonstrated, but its bearing 

 upon Lowit's theory of a connection of the giant cells with 

 the degeneration of the leucocytes seems to be very remote. 

 While it is true that we do not find in the lymph glands either 

 giant cells or degenerating leucocytes, that does not in any 

 way prove that the giant cells have any relation to the degen- 

 erative changes of the leucocytes. 3. In sections of the mar- 

 row, the giant cells are not found where erythroblasts and 

 leucoblasts are in active formation, but rather where the latter 

 show signs of degenerative changes. This statement I cannot 

 confirm ; indeed, it seems to me that the reverse is true, as 

 far, at least, as the erythroblasts are concerned, while with the 

 leucoblasts I have not been able to notice that in the neighbor- 

 hood of the giant cells there is any increase in the number of 

 them undergoing. degeneration. Foa and Salvioli have thought 

 that they were able to demonstrate a connection between the 

 giant cells and the nucleated red corpuscles. Their view, as 



