THE SKELETON. 29 



they agree in tlieir main physiological relations with the first class of 

 Noquez's Lymphatics : and the solid tissues of tooth and bone 

 manifest under the mici'oscope a system of nutrient vessels, which 

 were only hypothetically known to the older physiologists. I have 

 detected a similar system of plasmatic tubes in tendon ; and they 

 probably exist, under characteristic modifications, in all tissues, con- 

 stituting the essential nutritive system of such. 



The remains of the metamorphosed cartilaginous cells in bone 

 were first discovered by Purkiuje and Deutsch, (viii.), arranged 

 in concentric series around the Haversian canals : they be- 

 lieved them to be solid, and called them " corpuscula ossea." Tre- 

 viranus (ix.) first described them as cavities or " lacunar," in the 

 intervals of the concentric ossified lamellre, and he believed them 

 to be filled with fluid. Professor Mliller (x.) was led by the 

 whiteness of the radiated corpuscles when viewed by reflected light, 

 and by its disappearance, accompanied with evolution of gas, when 

 acted upon by dilute acid, to regard them as containing, either in 

 their parietes or cavity, calcareous salts. Serres and Doyere and 

 others have reproduced the idea of Treviranus, which is true to a 

 certain extent, but have erred in denying that the radiated cells 

 contain any calcareous salts, and have objected to the term " calci- 

 gerous" applied to those cells. But the effects of reaction of dilute 

 acid in removing the opacity of the cell when viewed by transmitted 

 light, and in removing its whiteness when viewed by reflected light, 

 show that these optical phenomena are not due to the mere depth of 

 empty cells : aggregated particles of the earthy salts become depo- 

 sited after the solution of the resisting nuclear matter upon their 

 parietes ; but the cavities are preserved by the slow but constant 

 percolation of the plasmatic fluids. Thus bone, like dentine, " pre- 

 sents a two-fold arrangement of its hai'deuing particles, which are 

 either blended with the animal matter of the interspaces and pai'ietcs 

 of the tubes and cells, or are contained in a minute and irregular 

 granular state in their cavities;" and "the density of bone, as of 

 dentine, arises principally from the proportion of earth in the first of 

 these states of combination." (v. p. iii.) 



The primitive arrangement of tlic osseous tissue, so composed, is 

 lamellar, the lamella; being arranged either concentrically around the 

 Haversian canal, or around the entire circumference of the bone, or in 

 interrupted plates connecting together the Haversian cylinders, and 

 those with the generally surrounding peripheral lamellae. 



The Haversian canals usually contain, in addition to the capillary 

 vessel, some oil, and this is the seat of the green colour in the bones 

 of the Belone and Lepidosiren. 



