CHICKEN BONE MARROW IN PLASMA MEDIUM 95 



(figs. 27, 9, and 38) have not changed their characters. They 

 abeady appear on the first day after incubation, because they 

 could be observed in bone marrow culture of 24 hours incuba- 

 tion. The elongated connective tissue cell is highly amoeboid, 

 and shows in its plasma, on the first days of incubation, fine and 

 bigger fat droplets, which are coarser when stained with specific 

 fat stains. Later their plasma looks as if pulverized with small 

 fat droplets, still later they lose their fat and appear highly 

 vacuohzed. They repeat on a smaller scale the changes of em- 

 bryonic subcutaneous connective tissue that had been incubated 

 14 days in a plasma medium. Because these cells appear after 

 the first day of incubation (the present author has observed them 

 after but five hours' incubation) it appears highly improbable 

 that they originated from the basophil spherical cells in question. 

 They are cells of the bone marrow network or the vessels of the 

 bone marrow, which have been torn apart by the cutting of the 

 bone marrow. They can be also observed in tissue cultures of 

 true adipose tissue and are distinguished by their rapid division 

 rate. 



In most cultures of connective tissue made by various authors 

 these cells have been described. Lambert and Hanes ('11) 

 mention the accumulation of fat and the vacuolization of 

 the cytoplasm in cells of mesenchymal origin. They repre- 

 sent tumor cells in their publication of 1911, plate 66, figures 4 

 and 5, of this character. Lambert himself in 1912, on plate 72, 

 figure 3 and plate 74 figures wandering cells from the chick 

 spleen. Some of these forms are more related to the connective 

 tissue cell type in question, some resemble more the cell type 

 seen in bone marrow cultures when the fat cells have begun the 

 disintegration. In 1914, plate 44, figure 6, he gives a good proof 

 of this. 



In figure 9, Carrel and Burrows, ('11), represent also fat stor- 

 ing cells of this type. They are said to be originated from an 

 adult chicken spleen, while the first author must have seen the 

 elongated vacuohzed type ('13, plate 17, figure 16), in culti- 

 vated connective tissue. Lewis, R. M., and Lewis, H. W., '11, 

 show on their figure 20, left side, in a chicken liver culture, 

 highly vacuohzed cells of the same type. 



