No. I.] BLOOD CORPUSCLES. OQ 



liarity of the extruding nucleus, not only from the study of 

 teased specimens stained in methyl green, but also from an ex- 

 amination of sections of marrow stained with haematoxylin, 

 eosin, and saffranin. It is not difficult to find in these sections 

 a nucleus in the act of extruding, and in all cases such nuclei 

 belonged to the mature nucleated red corpuscles as shown by 

 the fact that they stain with saffranin in preference to the 

 haematoxylin in the way that I have described. Osier (28), 

 who has figured and described the extruding nuclei, but does 

 not think they occur normally in the living tissue, states that 

 they are more abundant in the marrow twenty-four hours after 

 death than in the fresh cadaver. This may well be, even if 

 the phenomenon is a normal occurrence, since the marrow 

 cells probably survive some hours after somatic death, and the 

 mature nucleated corpuscles may lose their nuclei partially or 

 completely as in life, and the stoppage of the circulation would 

 lead to an accumulation of such examples in the marrow. 

 However, in the cat, at least, under the conditions mentioned, 

 they can be found in abundance immediately after death. 

 Whether or not with this animal the number is increased 

 twenty-four hours after death I have never determined. The 

 presence of granules within a newly formed red corpuscle has 

 been taken as a proof that the nucleus is absorbed within the 

 cell, the granules being looked upon as remnants of a former 

 nucleus. The existence of such cells cannot be questioned ; 

 but, taken alone, they cannot be considered as strong proof for 

 the theory of absorption nor as any objection to the theory of 

 extrusion ; for I have in a number of cases found red corpus- 

 cles containing these granules in which, nevertheless, the 

 nucleus was in the act of extruding, as shown in Fig. 2. 

 The granules in such cases evidently did not mean that the 

 nucleus had been absorbed. Erb (4), it will be remembered, 

 described such corpuscles in the circulating blood ; they form 

 his transitional stage between the white and red corpuscle. 

 Lowit (29^) has newly discovered them, especially in the blood 

 of certain veins after treatment with a modified Pacini's liquid, 

 and has laid great stress upon them as transitional forms be- 

 tween the erythroblasts and red corpuscles. Foa (41) also has 

 recently described granulations of this character as part of the 

 normal structure of every red corpuscle and easily brought out 



