THE MUCOUS TISSUE OF THE UMBILICAL CORD. ^99 



not say with certainty whence tho tissue of the umbilical 

 cord derives its nourishment ; perhaps it receives nutri- 

 tive matter from the liquor amnii, nor am I inclined to 

 deny the possibility of nutriments passing through the 

 walls of the vessels, or of the onward conveyance of 

 nutritive materials from the small capillaries of the per- 

 sistent portion. In any case, however, a large extent of 

 tissue lies at a distance from all vessels and from the 

 surface, and is nourished and supported without the pre- 

 sence of any minute system of blood-vessels in it. For a 

 long space of time, indeed, no one troubled himself any 

 further about this tissue, because it was designated by 

 the name of jelly, and thereby summarily ejected from 

 the number of the tissues and thrust into the ambiguous 



O 



group of mere accumulations of organic materials. I 

 was the first to show that it is really a well-constructed 

 tissue of a typical form, and that what constitutes the 

 ielly in the more restricted sense of the term, is the- 

 expressible part of the intercellular substance, after the 

 removal of which there remains a tissue containing a 

 delicate network of anastomosing cellular elements, simi- 

 lar to that which we have seen to exist in tendons and 

 other parts. A section through the external layers of 

 the umbilical cord exhibits a structure bearing great 

 resemblance 'to the external layers of the cornea; first, 

 an epidermoidal stratum, beneath it a somewhat denser 

 dermoid layer, and then the Whartonian jelly, which 

 corresponds in texture to the subcutaneous cellular tissue, 

 and is in some sort equivalent to it. This has a pecu- 

 liarly interesting bearing upon the tissues of a more 

 advanced period, inasmuch as, by thus ranking the jelly 

 with subcutaneous tissue, we at the same time establish 

 its very close relationship to the vitreous body, which is 

 the only remnant of tissue that, as far as I have until 

 now been able to make out, persists in man in this con- 







