IQ6 LECTURE IV. 



transverse anastomoses, and splitting up into smallei 

 and smaller vessels, which form fine networks within 

 the tissue, so that the whole of it is by this means map- 

 ped out into a series of -irregularly four-sided divisions. 

 To each of the ultimate intervascular spaces is allotted 

 a certain number of muscular elements, so that the ves- 

 sels are in some parts in contact with the muscular 

 fibres, whilst in others they lie at a greater distance 

 from them. 



If we go on in this way examining the structure of the 

 different organs and tissues, we pass from such as, when 

 injected^ seem to consist almost entirely of vessels, in 

 time to those which contain scarcely any, and at last to 

 such as really have none at all. This is most strikingly 

 the case with the connective tissues, and the most im- 

 portant amongst these are bone and cartilage. Perfectly 

 developed cartilage has no longer any vessels at all ; 

 perfectly developed bone certainly contains vessels, but 

 in a very variable degree. That perfectly developed 

 cartilage contains no vessels, you will not, I suppose, call 

 upon me to convince } r ou by any additional, special 

 proofs, inasmuch as you have seen various prepara- 

 tions of cartilage, in which not a trace of them was to 

 be observed. (Figs. 6, 9, 22.) I now place before you 

 a piece of young cartilage, because you can see in it 

 what the arrangement of the vessels in cartilage is at 

 an earlier period. It is a section from the calcaneum of 

 a new-born child, and in it the vessels run up from the 

 already-formed central osseous mass into the cartilage 

 which still remains. The preparation shows along the 

 outermost surface of the cartilage the transition from it 

 into the perichondrium, whilst the lower part of the sec- 

 tion is taken from the border of the already-formed 

 bone. From this part large vess3ls are seen running 

 up and terminating in the middle of the cartilage by 



