XHL] BONE, OSSEOUS TISSUE, ETC. 179 



t 



and from which the acid has been removed by steeping in water, 



and subsequently in spirit) with forceps remove the periosteum, and 



tear off a thin lamella of 



osseous tissue. Place its 



under-surface uppermost on 



a slide in water or v. 



Ebner's fluid. 



(H) Observe fine tapering 

 fibres like nails perforat- 

 ing fibres projecting from ^ z - 

 the surface. Some aper- 

 tures may be found from 



which corresponding fibres v x,-^ _^-- / ; 



have been withdrawn. . . - ' 



(ii) These are far better FlG . I50 ._ T . S . of alarge Hav.rsia^anal with its 



developed 111 the bones of Soft Parts. Femur of a Doff, x 130. A. Aitcry; 



i v 1 n f -U- j Q (i. V. Vein ; Kz. Bone-cells ; M. Medullary tissue ; 



the skllll Of birds. Soften O bl. Osteoblast ; pkl. Osteoclast. 



the vault of the skull of a 



fowl in v. Ebner's fluid and harden in alcohol. Make not too thin 

 sections, and with needles tear the lamellae asunder. Examine it 

 in v. Ebner's fluid. Or make sections of a human frontal bone 

 softened in dilute hydrochloric acid, and examine it in water. 



(H) Numerous perforating fibres passing between the separated 

 lamellae, and, it may be, the sockets from which they have been 

 withdrawn, will be seen (fig. 

 151). In some of the sections 

 branched perforating fibres are 

 visible. The important point 

 is to make the sections as S \ I I 1 



nearly as possible parallel 1 v / V^ 



the course of the fibres. The < 

 preparation is apt to be made '> ij^ / "r^'^-^&r- 

 too transparent by Farrant's 

 solution, so that the fibres are 



not SO distinctly seen in this *'W. 151. Sharpey's Perforating Fibrus. 



medium as in water or v. 



Ebner's fluid. Observe that there are no Sharpey's fibres in the 



Haversian systems. 



5. Blood- Vessels of Bone (L). These are not easily injected. 

 Inject with a fluid carmine mass (p. 89) the posterior half of 

 the body of a rabbit. Do this from the alxlominal aorta. Or use 

 the injection fluid mentioned at p. 181. It requires considerable 

 pressure to cause the injection to traverse the blood-vessels of bone. 

 Therefore clamp the inferior vena cava to prevent the exit of the 

 injection mass. Decalcify the injected bone, and afterwards make 



