XIV.] 



BONE AND ITS DEVELOPMENT. 



187 





variety of corpuscle. They exhibit amoeboid movements under 

 proper conditions. 



(2.) Cells with Budding Nuclei (fig. 161). Far less numerous, 

 but easily distinguished, are large finely granular cells, each with 

 a single large, often twisted, nucleus, which in some looks as if 

 it were composite, in others it would seem to consist of several 

 parts united by some 

 substance like the nuc- 

 leus itself. There is 

 very great variety in the 

 shape of those nuclei, 

 which are visible in the $ 

 fresh condition of the * 

 cell. These cells are fi ' 

 not amoeboid (fig. 161. 

 //, i). 



(3.) Myeloplaxes. - 

 These are larger than 



the, foregoing, consisting FIG. 161. Cells from the Red Marrow of the Tibia of a 



^f o ^,, Q l-,r mlo-r. Young Rabbit, a, b, c. Marrow-cells examined in 



iciy gra normal saline ; rf, e. Marrow-cells after dilute alco- 



protoplasm with liumer- ho1 ? /. 9- After dilute alcohol; h, i Large cells 



i . / n .. \ with budding nuclei ; m. Myeloplaxes. x 300. 



ous nuclei (fig. 161, m). 



What relation there is between (2) and (3), or if there is any relation 



at all, is entirely unknown. 



(4.) There are to be found cells smaller than but not unlike (i), 

 with a homogeneous protoplasm which has a reddish tint and a 

 spherical nucleus. Some of them have a small bud at the side 

 (fig. 1 6 1, /, g). They are regarded as cells from which coloured 

 blood-corpuscles are formed. They are regarded by Bizzozero as 

 similar to the nucleated red blood-corpuscles of the embryo. 



(5.) Always a few fat cells. 



(6.) Numerous red blood-corpuscles from the blood-vessels in the 

 red marrow. 



(7.) Sometimes osteoblasts may be detached along with the other 

 constituents of the marrow. 



Lay open a rib or a long bone of a guinea-pig or rabbit ; remove 

 a little of the red marrow and diffuse it in blood-serum or normal 

 saline. With a high power search for examples of each of the 



foregoing kinds of cells, 

 from it the red marrow 



The vertebra of a calf may be used, and 

 is readily expressed by squeezing it in a 



vice. 



The, nuclei in some of the cells are best revealed by the action of 

 dilute alcohol. 



5. Red Marrow. (i.) Squeeze out some of the, red marrow from 

 a rib of a guinea-pig or rat; shake it in a test-tube containing 



