CHICKEN BONE MARROW IN PLASMA MEDIUM , 85 



the quicker they undergo destruction holds true in the case of 

 erythrocytes. The red blood corpuscles appear often without a 

 nucleus or without a shadow of a nucleus. The plasma seems 

 perforated. This indicates that the haemoglobin has disap- 

 peared. Those cells in which we can trace only the shadow or 

 a faint remainder of the nucleus are apt to deceive the observer. 

 The remainder of the nucleus appears like a small parasite but 

 is nothing more than the nucleus of the cell, as can be proved by 

 numerous intermediate forms. These bodies resemble the Cabot's 

 bodies which are described by Juspa ('14, p. 429) in certain 

 diseases of men. Also the nuclei may become pyknotic in other 

 forms and the plasma may disappear. Foot ('12, p. 461, and 

 1913, p. 46) notes these same two different ways of degeneration 

 in erj^^throcytes. Their dead nuclei or their plasma is often 

 incorporated into phagocytic cells (figs. 34 and 35) the origin 

 and types of which will be discussed later. 



The non-elongated round or irregularly shaped erythroblasts 

 have a pale yellowish or colorless plasma (figs. 1 to 3). Well 

 developed erythroblasts are distinguished when stained by their 

 wheel-like, highly chromatic nucleus. Unstained cells show a 

 whitish appearance of the nuclear membrane which seems 

 crowded with the content of the nucleus and ready to break. 

 Figures 3 and 7 represent erythrocytes and erythroblasts in vari- 

 ous stages of their retrograde development. Their plasma-less 

 nuclei cover the microscopic field and are often seen incorporated 

 into cells of phagocytic character. Unripe, young erythroblasts 

 are figured in figure 8. They have larger nuclei in proportion to 

 their basophil plasma than the erythrocytes and are scattered, 

 through the tearing apart of the bone-marrow network, in large 

 quantities into the surrounding plasma. They are recognizable 

 in stained preparations by the smooth surface of their plasma 

 and their chromatic nuclei and cannot be confused with ''eine 

 Art von basophilen mononuclearen Zellen" which, according to 

 Foot '12, form the X cells and the cell culture type. 



But the difficulty begins when very young, i.e., small cells 

 characterized in the first day of incubation by their situation 

 near the bone-marrow network, are to be isolated and cultures 



