96 GENERAL ANATOMY OF THE TISSUES. 



proposed the denomination of mucous tissue {tissu muqueux) for it. I 

 considered it from the first to be connective tissue, and I now feel the 

 more inclined to remain of this opinion, because I find that every de- 

 scription of the areolated connective tissue of embryos originally com- 

 mences under this form, and therefore the circumstance that the tissue 

 in the umbilical cord never arrives at perfection, cannot determine its 

 nature. 



The mode in which the gelatiniform connective tissue is developed is 

 this : one portion of the cells contained in the gelatinous basis changes 

 into connective tissue by becoming fusiform, and breaking up into common 

 or reticulated anastomosing connective tissue, which, however, as Schwann 

 has already stated, at first yields no gelatine. In this manner a closer or 

 denser network arises, in the interspaces of which the intermediate sub- 

 stance or matrix, and a remainder of the previous formative cells, are 

 contained. In the further course of development, new cells proceed 

 from the matrix, which hereby diminishes by degrees in quantity, and 

 at the same time the original network consolidates, fresh cells being 

 added to it, a part of which also become elastic fibres and vessels. If 

 subsequently the areolated connective tissue includes no adipose cells, 

 the gelatinous tissue ends by completely disappearing, and nothing re- 

 mains but a loose fibrous tissue, containing at most somewhat less fluid, 

 and loose cells in its meshes ; if, on the other hand, it becomes con- 

 verted into an adipose tissue, the spaces remain, and a great part of the 

 cells which have arisen at the expense of the gelatinous substance, sub- 

 sequently pass, by the development of fat in their interior, into fat- 

 cells. 



In the gelatinous tissue of Wharton, between the chorion and amnion, 

 and in part of the enamel organ, the areolated connective tissue remains 

 more in its foetal condition of a gelatinous tissue, yet there exists no 

 natural line of demarcation from ordinary connective tissue, so much 

 the less, since in the gelatinous substance of Wharton, in older embryos 

 even fibrils are quite evident, and in the enamel organ the passage of a 

 part of the gelatinous tissue into common connective tissue is demon- 

 strable. 



So much for the two types of development of the connective tissue. 

 We have yet to state how the bundles become chemically and morpho- 

 logically what they are. In the first place, I may observe that the for- 

 mative cells of the connective tissue are not originally distinguishable 

 from the other formative cells of the embryo, do not dissolve by boiling 

 in water, and therefore contain no gelatine. Even when the cells have 

 evidently become fusiform, and have already coalesced into bundles and 

 networks, they still, as Schwann has already stated, yield no gelatine. 

 Therefore, in this case, the change of the cells into a collagenous sub- 

 stance, goes on as slowly as in the matrix of the cartilages, which, 



