86 PRACTICAL HISTOLOGY [XI 



8. Hcematoblasts. Cut out a rib of a freshly killed rat or 

 other mammal, scrape off the external tissue, cut it open, 

 remove a little of the red marrow to a cover-slip and spread it 

 out making a dry film. Stain with eosin and methylene blue as 

 in the case of a blood film (p. 18), but leave 2 to 3 minutes in 

 the eosin, arid 1^ to 2 minutes in the methylene blue. 



Note (h. p.) the hasmatoblasts with cell substance stained 

 orange, and rather small deeply stained nucleus. Numerous 

 coarsely granular leucocytes with granules stained red will be 

 seen, also oxyphil cells with large faintly stained nucleus, 

 basophil cells faintly stained (without distinct granules) and 

 other leucocyte forms. 



9. Ossification. Longitudinal sections through 

 the head of the femur of a newly-born (or foetal) cat or 

 rabbit (picric or chromic acid). Stain with hsematoxylin 

 and eosin, mount in balsam. 



Observe (1. p.) passing from the head to the shaft 



The normal hyaline cartilage. 



The longitudinal rows of cartilage cells; many of 

 the cells are triangular in section. The layer of large, 

 probably shrunken, cartilage cells; they are also in 

 rows and have only a small amount of matrix around 

 them. 



The irregular spaces (secondary areolse) of the 

 primary endochondral bone. The bony trabeculse 

 may show a thin central portion of decalcified cartilage 

 stained with hsematoxylin 1 . 



Note on the outside of the bone below the head, 

 the periosteum, and the layer of spongy periosteal 

 bone beneath it. 



1 The two parts are also distinct in sections stained in the 

 Ehiiich-Biondi mixture. 



