174 MR. TOYNBEE ON THE ORGANIZATION AND NUTRITION 



2. Flbro- Cartilage. 

 Of the Structure of Fibro- Cartilage. 



Anatomists of all ages have recognized the existence of a distinct animal tissue, 

 partaking of the properties of both cartilage and ligament. Respecting the exact 

 nature and composition of fibro-cartilages, the opinions of anatomists have differed 

 considerably. 



Meckel states that in them " the fibrous and cartilaginous tissues form layers 

 which alternate more or less regularly*." 



BiCHAT considered them to be composed " of a fibrous substance more than of a 

 true cartilage." 



Dr. Todd describes them as having '^ a very complicated cellular structure, com- 

 posed of minute meshes, very irregular in size and shape -f." 



MiJLLER describes them as follows : — " The interarticular cartilages, the interver- 

 tebral cartilages, and the cartilages of symphyses are constituted wholly of fibres, 

 and contain none of the corpuscles peculiar to cartilages J." 



One of the most recent and able investigators in the branch of anatomy under 

 consideration is Miescher, and his opinion agrees with that of Muller ; he states 

 that in the interarticular cartilages of the knee, which in infants E. H. Weber con- 

 sidered to be true cartilage, " he found both in infants and adults only the fibrous 

 structure and no trace of corpuscles §." 



Weber states that " the intervertebral substance exhibits no intermixture of car- 

 tilaginous substance II ." 



Fibro-cartilages consist, as their name implies, of both fibrous and cartilaginous 

 tissue ; that is to say, I have always found them to be composed of minute fibres, 

 and of the corpuscles characteristic of cartilage. 



Fibro-cartilages may with accuracy be divided into two classes, both entering into 

 the structure of joints. 



The Jirst class exists in those articulations which admit of only a slight degree of 

 motion, and which are deprived of a synovial membrane. Such are the intervertebral 

 Jibro-cartilages, and thejibro-cartilages of symphyses. 



Fibro-cartilages of the second class are generally called the interarticular. They 

 differ from those of the first class in being more or less free, and in having both 

 surfaces covered by synovial membrane ; they are situated between the extremities of 

 bones which are covered with articular cartilage. 



In both classes the fibrous portion of the tissue is most abundant towards the 



* Manuel d'Anatomie, Generale, Descriptive et Pathologique, vol. i. p. 363. 



t Encyclopaedia of Anatomy and Physiology, vol. ii. p. 261. 



X Translation of Muller's Elements of Physiology by Baly, vol. ii. Appendix, p. 4. 



§ Miescher, p. 29. [1 Ibid. 



