7S RHODA ERDMANN 



discovery of fat were added (see descriptions of plates, page 118. 

 Besides these, the Giemsa stain after moist fixation according to 

 the prescription of Giemsa proved to be very satisfactory. No 

 dry smears of bone marrow were used. 



THE FATE OF LIVING BONE MARROW CELLS IMPLANTED IN 



PLASMA AT 38°C. 



The experiments from which the drawings on plates 1 and 2 

 were made were started on December 25, 1915, and on January 

 3, 1916. The bone marrow was taken from a full-grown chicken 

 which had a large amount of fat, so that the pieces of marrow 

 have a yellowish-white appearance. The first cells to leave the 

 tissue after 40, 60, and 90 minutes incubation are, as Foot 

 rightly remarks in his publication of 1913 (p. 49), small 

 mononuclear or larger polymorphonuclear leucocytes (fig. 1). 

 The forms have a very dark, granulated cytoplasm and are 

 actively amoeboid (fig. 1). Pale mononuclear forms without 

 granulations but with their characteristic vesicular nucleus, 

 follow closely the emigrating polymorphonuclear leucocytes. 

 The fourth cell from the left (fig. 1) represents an erythroblast. 

 The structure of the nucleus makes this evident. Besides these 

 forms figured in figure 1, red blood corpuscles and a few fat 

 cells were present in those parts of the plasma clot which sur- 

 round the implanted bone marrow particle. The network of 

 the bone marrow was injured by the process of cutting and tear- 

 ing the particle into small pieces, and it is therefore not sur- 

 prising that a large number of red blood corpuscles and some 

 fat cells were scattered into the surrounding plasma clot. They 

 are not figured in figure 1. 



After 24 hours various other cell types have migrated into 

 the surrounding plasma. 



Figure 2 shows bone marrow which has been in the plasma 

 for 24 hours, from January 3 to January 4, 1916. We can easily 

 distinguish two different kinds of granulocytes: big cells which 

 have round, shining granules, the nucleus nearly half as big as 

 the cell and half-moon shaped; and smaller forms, with very 

 dark granules, the latter not rounded but more rod-shaped, the 



