QUAllTERLY CHRONICLE OF AIICKOSCOI'ICaL SCIKNCE. 41 5 



1873), finds, on examination of sections through the jaw 

 prior to the formation of the tooth-sac, that many giant-cells 

 contain clear round or oval holes of various sizes. The larger 

 and more distinctly defined ones, in the centre of vs^hich a 

 debris resembling fatty particles is sometimes to be detected, 

 appear to be originated by a disintegration of minute portions 

 of the protoplasm of the giant-cell. From this the author 

 takes it as possible that the giant-cells, after having ceased to 

 exercise their destructive, i. e. absorbing function, become 

 disintegrated. Morison takes it also as probable that sequestra 

 are separated from living bone by means of giant-cells, for, 

 on examining a fresh sequestrum from a case of necrosis uf 

 the tibia, there were found Howship's lacunse covering all 

 aspects of the sequestrum, and the blood and pus around 

 the preparation contained multinuclear giant-cells floating 

 about. 



As regards the origin of giant-cells, Morison agrees with 

 Kolliker and others that many of them are in genetical con- 

 nection with the osteoblasts, but that others probably develop 

 from embryonic connective tissue ; for there occur bone-spaces 

 with here and there a giant-cell entirely destitute of osteo- 

 blasts, but containing the nuclei of embryonic connective 

 tissue. These nuclei, generally scattered, are here and there 

 closely aggregated and show an intern uclear opacity, which, 

 however, has not the distinctly granular appearance of the 

 opaque cell-substance of a fully developed giant-cell; but this 

 appearance is in variable degree, even in fully formed cells. 

 It is possible that the aggregation of nuclei may be the first 

 stage in the formation of a giant-cell ; one has only to 

 imagine that these nuclei prepare a cell-material each 

 around itself, which, coalescing with that round its neigh- 

 bours, produces the multinuclear giant-cell. — E. Klein, M.U., 

 in ' London Medical Record.'' 



14. On the Absorption of Bone. E-ustizky (' Virchow's 

 Archiv.,' lix., p. 202) confirms the presence of giant-cells in 

 normal and pathological absorption of bone. He finds that 

 there are three modes in which they occur, either only in a 

 single layer immediately on the surface of the affected portion 

 of bone, or also in the periosteum ; or lastly, also, in the 

 interior of the bone. The presence of giant-cells could not 

 be shown in all cases of bone-absorption, and notably not in 

 the little depressions formed on the inner surface of the 

 calvaria by the Pacchionian bodies, nor in a sternum which 

 was partially atrophied by the pressure of a hypertrophied 

 heart. Hence the author does not accept Kolliker and 

 Wegener's views, that long-continued pressure against a bone 



