EXCESS IN VOLUME OF THE FCETUS. 



373 



longation of gestation beyond its ordinary period ; though this suspicion, 

 as we have seen, will not always, nor yet very often, be confirmed. 



It is only, then, at parturition that this obstacle on the part of the foetus 

 can be ascertained. If at this time, in spite of energetic and sustained 

 uterine contractions, labor is protracted and does not advance, and if 

 on exploration the pelvis and genital organs are found to be well-formed 

 and normal, the os dilated, the foetus in a favorable position and not 

 malformed, it may be suspected that the obstacle to birth is dependent 

 on the large size of the latter. A closer examination will probably con- 

 firm this suspicion. 



With the Bitchy the principal obstacle, as has been already said, is gen- 

 erally with the head of the puppy, which, when it is large, is lodged at 

 the entrance to the pelvic inlet, where it can be touched/*?/- vaginam. 



The common-bred Bitch, with muzzle more or less elongated, when 

 fecundated by a male of the same size and conformation, and bringing 

 forth from five to eight young, has usually no difficulty in pupping. The 

 tapering or conical form of the muzzle of the puppies allows it to enter 

 the passage and pass easily through, under the influence of the uterine 

 and abdominal contractions. But when the Bitch is of small size, and 

 has been impregnated by a larger and young vigorous dog, and especially 

 if the muzzle of either or both of the parents is short and the cranium 

 brachycephalic — as in King Charles' spaniels, pugs, and bull-dogs — par- 

 turition is oftentimes extremely difficult, as the forehead in these breeds 

 is very large and cylindrical. This difficulty, as has been mentioned, is 

 increased as the number of puppies is small, as then the latter are more 

 developed. 



With the Cow, the head of the calf may also be the chief impediment, 

 and provided the young creature is otherwise in a favorable position, 

 the muffle may pass through the inlet, but the remainder of the head re- 

 mains fixed like a wedge in the long and almost undilatable bony canal. 

 The head is often so firmly wedged at this part that it can scarcely, even 

 with much force, be advanced or pushed back, and this " wedging " is 

 always one of the most serious difficulties which the obstetrist has to 

 overcome. 



With the Mare, the head of the foal is smaller, longer, and more taper- 

 ing than that of the calf, and meets with much less resistance in passing 

 through the comparatively short and wide canal. But as Saint-Cyr points 

 out, and as we have previously shown, in the equine and bovine species 

 the young creature finds more difficulty when the anterior part of its body 

 — chest and shoulders — begins to enter this part ; and from their respec- 

 tive dimensions it is evident that, even under ordinary conditions, the 

 anterior region of the foetal trunk must submit to a certain degree of 

 diminution in order to pass the pelvic inlet of the mother. 



The limits within which this diminution is compatible with physiologi- 

 cal parturition, are not yet perfectly ascertained ; though there can be 

 no doubt whatever — for we have facts to prove it — that the development 

 of the young creature may be so exaggerated that sufficient reduction 

 cannot be effected to allow of its being born. 



Mignot, of the Agricultural School at Saulsaie, France, furnished Saint- 

 Cyr with the following notes and measurements which he made of a case 

 of protracted parturition due to this cause. 



An Ayrshire Cow, aged three years and ten months, i'30 metre high, and weighing 



