178 APPENDAGES OF THE FOETUS. 



am no.w in possession of several of from one fortnight to three weeks 

 old, which are only three or four lines long, and in which the cord 

 is equal to, or even exceeds the length of the foetus. Relying upon 

 very numerous facts, I think I can establish it as a general rule that 

 the length of the cord is about equal to, or somewhat exceeding that 

 of the foetus, at all periods of pregnancy. 



It is slender and cylindrical until the end of the third week: a 

 little later from the fourth to the seventh, the eighth, or even the 

 ninth week, it acquires a considerable relative size, exhibits tuber- 

 cles, vesicles or swellings, which I have no where seen described, 

 which are to the number of two, three or four and separated by the 

 same number of contractions. In the course of the third it becomes 

 smaller, in consequence of the shrinking away of its swellings; 

 finally, from this period until the termination of pregnancy it ceases 

 to grow in proportion to the other parts of the foetus. 



464. Its composition is far from being the same at all stages of its 

 evolution. At the commencement, it really consists only of a small 

 solid cylinder, to which the amnios does not furnish any coat. From 

 the fifth week it contains the duct of the umbilical vesicle, and a por- 

 tion of the urachus or allantois, and some of the intestines. But 

 about the second month, the alimentary canal has re-entered the 

 abdomen, the urachus, the vitelline duct and its vessels have become 

 obliterated, so that at three months, as at nine, the umbilical stem is 

 formed only of two arteries, the vein of the same name, of the gela- 

 tin of Warthon or spongy tissue of Rouhault, and of the amniotic 

 sheath. 



465. DiemerbroBck, Wrisberg, Schroeger, and Michaelis have ad- 

 mitted the existence of lymphatic vessels in the cord; MM. Chaus- 

 sier, Darr, Reuss, &c. think they have discovered nerves in it going 

 to the solar plexus; but it is probable these authors permitted them- 

 selves to be imposed on by some remains of the urachus, the vitel- 

 line vessels or duct, &c. At least I have never been able, with all 

 the pains I could take to verify their assertions; a circumstance in 

 which my researches agree with those of MM. Lobstein and Meckel. 



466. Although there is in man only one umbilical vein, as an 

 ordinary rule, cases are cited where there were two, as occurs in a 

 great many of the mammiferae. In other cases, instead of two arte- 

 ries, only one is found; I have seen an instance of this sort, and M. 

 Blandin has deposited a second in the Museum of the Faculty. 



These vessels are not visible until the first fortnight, or the second 

 month after conception, and do not assume the spiral form until after 

 the disappearance of the swellings of the cord, that is, from the 

 seventh to the eighth week. The reason of this twisted appearance 



