CONNECTIVE TISSUE. 219 



R. Virchow * claimed that the lacunar and canalieular spaces are really 

 plasmatic, and can be isolated, as true " bone-cells," by the treatment of 

 dry bone with acids. He was contradicted by E. Neumann, t who con- 

 clusively proved that Virchow's branching cells are nothing but the densified 

 walls of the lacunae and the larger canaliculi resisting the action of strong 

 acids and alkalies (elastic substance). Such a substance was found to line 

 also the Haversian canals. 



A. Kolliker \ declared that on the external surfaces of growing bones an 

 absorption takes place. Virchow, in 1853, agreed that such an absorption 

 occurs on the cerebral surfaces of the skull-bones. Virchow had, in 1852, 

 asserted that the bay-like excavations (so-called Howship's lacuna) on the 

 surface of pathological bones are due to a melting of the substance of the 

 bone, in correspondence with the cell territories ; afterward, he maintained 

 that the bone-cells set free by the solution of the intercellular substance, are 

 transformed into medullary cells. 



Tomes and De Morgan || observed erosions in carious and provisional teeth, 

 and argued in the following manner : " When we connect this condition with 

 the fact that the nucleated cells, which form the embryo, have the power of 

 appropriating the material which lies about them to the purpose of their own 

 growth, ... it is difficult to resist the belief that the cells which lie in con- 

 tact with wasting bone and dentine take up those tissues. . . . An objection 

 may be raised to the supposition that the bone is absorbed by cells, on the 

 ground of the density of the former ; but it must be borne in mind that, as 

 the density is gradually imparted to the bone through the agency of the 

 adjoining soft parts, there seems no good reason for disbelieving that they 

 may also be instrumental in its removal." 1f 



Heinrich Miiller, in 1858, 1 published his epoch-making researches on 

 development of bone, which are the foundation of our modern views on this 

 subject. His observations will be dwelt upon in the article on development 

 of bone. Reference will there also be made to the researches of Gegenbaur 

 (1865) and Waldeyer (1865). 



Ed. Lang 2 was the first to ascertain that, in bone-specimens of recently 

 killed animals, the lacunae contain protoplasm, which is, to a certain degree, 

 endowed with the property of amoaboid motion, and from which starts the 

 inflammatory new formation. 



In the last decennium, a lively controversy was carried on regarding the 

 question whether or not a growth of the bone by expansion, a so-called inter- 

 stitial growth, occurs. 



Ruge, 3 as the result of his counting and measuring the distances between 

 bone-corpuscles, became a defender of the theory of interstitial growth. Jul. 

 Wolff 4 energetically maintained an interstitial growth, and denied any appo- 



* " Wiir/.burger Verhandlungen," 1850. 



f'Beitrage zur Kenntniss des norm. Zalmbein- und Knochengewebes." Konigsberg, 

 1863. 



t " Mikroskopisclie Anatomic," 1850. 



$ Virchow's Archiv, Bd. iv. 1852 ; Bd. v. 1858. 



|| " Observations on the Structure and Development of Bone," 1852. Philosophical 

 Transactions, 1853. 



II All quotations from authors in this historical sketch are from Kolliker (I. c.). 



1 "Zeitschrift fur Wissensch.-Zoologie." Bd. ix. 



2 " Uutersuchuugen iiber die ersten Stadien tier Kuochenentziindting." Wiener Mediz. 

 Jahrb., 1871. 



s Virchow's Archiv. Bd. 49. 4 Virchow's Archiv. Bd. 50. 



