88 OBSTETRICAL PHYSIOLOGY. 



Bitch and Cat. 



In the Bitch and Cat the cord resembles that of solipeds, in having an 

 allantoic portion, but it is extremely short, and enveloped in a large fold 

 of allantois. The omphalo-mesenteric vessels are very apparent until 

 the end of gestation, and are proportionately larger than in solipeds ; 

 this is due, in all probability, to the persistence of the umbilical vesicle. 

 These are an artery and a vein ; the former arises from the anterior 

 mesenteric, descends in nearly a direct line to the umbilical opening, 

 and is expended in the umbilical vesicle. The vein originates from the 

 terminal divisions of the artery, passes towards the abdomen, and ter- 

 minates in the vena porta. 



The dimensions of the umbilical cord vary with the species of animals. 

 Compared with that of the human foetus, it is short in solipeds and 

 ruminants. At the commencement of gestation in the Mare and Cow, it 

 is not so long as at a later period, though it is thicker ; towards the 

 termination of gestation, it is at least as long as the young animal is tall. 

 Its length in the Mare has been variously estimated. Immediately 

 before birth it has been found to measure three feet four inches long, 

 and three and a half inches in circumference (three-fourths in diameter). 

 Daubenton found it to be in one instance, from the umbilicus to the am- 

 nion, eighteen inches, though the period of gestation is not mentioned. 

 Bourgelat gives it as about two and a half feet ; Blaine, from two^ to 

 two and half feet. Goubaux found it to measure, when untwisted, at six 

 months' pregnancy, thirty-four inches ; but it was so very twisted (twelve 

 turns) that in this state it was only twenty-nine inches in length. 



In the Cow, Vitet gives it as from nine to ten inches ; but Goubaux, in 

 a Cow at the eighth month of pregnancy, found it to be about sixteen 

 inches ; while Colin, in another Cow at the same period, gives eighteen 

 inches. 



In the Sheep, at two months' gestation, it has barely measured one 

 inch ; Rainard, at the end of gestation, gives it at from three-fourths to 

 one and a quarter inches. Daubenton says it is two inches at parturition. 



In the Pig it is comparatively very long, sometimes stretching the whole 

 length of the Pig. Daubenton found it to be one incli^in length in a foetus 

 measuring three inches, and three lines from nose to anus. 



In the Bitch and Cat it is very short, and measures from one to two 

 inches at birth ; or about two-fifths of the length of the body. 



In the early days of foetal life, the cord contains a portion of the intes- 

 tines, but as the cavity of the abdomen is formed and closes, the viscus 

 is retracted within it. Very rarely, however, this retraction is not com- 

 plete, and hernia of the intestines exists at birth, or even some time after 

 that event. 



With regard to the curious torsion of the cord on itself, it has been held 

 by some authorities that this is only accidental, and depends on the 

 movements of the foetus during the latter stages of gestation, or the dis- 

 placement it undergoes on leaving the uterus; consequently, that the 

 spiral twisting of the vessels is not normal. Examination of non-dis- 

 placed foetuses jDroves that it is far from being constant. 



At birth, the umbilical cord is usually torn or gnawed through, at a 

 short distance from the umbilicus of the foetus ; the remaining portion 

 drying up, dying, and falling off in a few days. 



