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XIII. Researches, tending to prove the Non-vascular ity and the peculiar uniform Mode 

 of Organization and Nutrition of certain Animal Tissues, viz. Articular Cartilage, 

 and the Cartilage of the different Classes of Fihro-Cartilage ; the Cornea, the 

 Crystalline Lens, and the Vitreous Humour; and the Epidermoid Appendages. 

 By Joseph Toynbee, Esq., Member of the Royal College of Surgeons, London, and 

 late Assistant to the Conservators of the Museum of that Institution. Communi- 

 cated hy Sir Benjamin C. Brodie, Bart. F.R.S. ^c. S^c. 



Received April 21, — Read May 20, 1841. 



Introduction. 



XT is now generally acknowledged that the process of nutrition in most animal 

 tissues consists in changes undergone by the nutrient liquor sanguinis, which has 

 exuded into them through the coats of the capillaries ramifying throughout them. The 

 vessels themselves vary in number in different structures ; in muscle, the capillaries 

 are very numerous, and the spaces between them very small ; whilst in tendon and 

 ligament, on the other hand, the latter are comparatively large ; but in all structures, 

 whatever may be the degree of their vascularity, the tissue the furthest removed 

 from the vessel is nourished equally well with that which is in immediate contact 

 with it. 



In all vascular structures, therefore, there is of necessity a considerable extent of 

 tissue which is nourished without being in contact with blood-vessels, and the know- 

 ledge of this fact forms a necessary introduction to the study of the process of nutri- 

 tion in those organs, into which, whilst in a healthy state, anatomists have never 

 succeeded in tracing blood-vessels. The organized tissues, constituting such non- 

 vascular organs, may be divided into three classes : 



The first, comprehending articular cartilage, and the cartilage of the different 

 classes of fibro-cartilage ; 



The second, the cornea, the crystalline lens, and the vitreous humour ; 



The third, the epidermoid appendages, viz. the epithelium, the epidermis, nails 

 and claws, hoofs, hair and bristles, feathers, horn, and teeth. ^ 



It is to these tissues that the investigations I have now to communicate relate : I 

 shall endeavour to prove that no vessel ever enters them when they are perfectly 

 developed, and in a healthy state, and to demonstrate the manner in which they are 

 nourished. 



In the first place, no anatomist has ever been able to trace vessels into these tissues 



