411 QUARTERLY CHRONICLE OK xMICROSCOPICAL SCIENCE. 



upon the capsule they are epithelioid. These cells, whether 

 possessing processes, or arranged like an epithelium, must be 

 looked upon as connective-tissue corpuscles. In the synovial 

 membrane itself Reyher also denies the existence of an 

 epithelium. . Places may be found on the inner surface of the 

 capsule with the cells regularly arranged, but these patches 

 are never extensive. The irregular branched form of cells 

 persists throughout life on the inner surface of the capsule ; 

 but on the surface of the cartilage a change occurs, depending 

 on the growth of the articular surfaces and on the varying 

 conditions of contact and pressure to which they are exposed. 

 On concave articular surfaces, whose growth is more or less 

 uniform both near the centre and at the periphery, the cells, 

 whether epithelioid, stellate, or rounded, are more or less 

 similar throughout; whereas on convex surfaces, such as the 

 head of the humerus or femur, the superficial cells near the 

 neck are far less separated than those nearer the centre of the 

 articular surface, when growth and development are more 

 rapid. Again, in parts of the surface which are always in 

 contact, the epithelioid cells become as development pro- 

 ceeds irregularly stellate, finally losing their processes and 

 becoming round, so that at birth the epithelioid arrangement 

 has mostly disappeared. The converse had been already 

 shown by Reyher by keeping the joints of dogs at rest, so 

 as to remove all effects of pressure and movement. The cells 

 on the articular surfaces then again take on a more or less 

 epithelioid arrangement, accompanied by an absorption of 

 intercellular substance, and this extends also to the deeper 

 layers of the cartilage. Hence the synovial process is not to be 

 looked upon as an ingrowth of the synovial membrane as, 

 some have asserted, but rather as being formed in sitil as the 

 development of the joint proceeds, its cells being intimately 

 related both by the history of their development and by the 

 presence of intermediate forms with the cartilage cells of the 

 articular surface. 



11. Development of Bone. — Ranvier (' Quelques faits 

 relatifs au Developpement du Tissu Osseux,' ' Comptes 

 Rendus,' 1873, ii, Ixxvii, 1105; ' Centrablatt,' 1874, p. 452). 



12. Connective Tissue of the Spinal Cord. — Ranvier 

 C Comptes Rendus,' 1873, ii, Ixxvii, 1299; Centralblatt,' 

 1874, p. 483) contends that this is similar to the connective 

 tissue of the peripheral nerves. 



13. Bone- Absorption hy Means of Giant-Cells. — Mr. 

 Alexander Morison (' Edinburgh Medical Journal' for October, 

 1873), taking up the researches of Kolliker on absorption of 

 bone by means of giant-cells (see ' London Medical Record/ 



