PREMATURE EXPULSION OF THE FCETUS. 913 



that of the Fallopian tube, or to any other organ. It is an additional indi- 

 cation that the immediate stimulus to the parturient effort of the uterus is 

 given by some change iu the condition of its foetal connections, that the term 

 of gestation seems capable of being prolonged by peculiarities in the consti- 

 tution or rate of development of the foetus, which are derived from the male 

 parent ; for it was ascertained by the late Earl Spencer, 1 that of 75 cows in 

 calf by a particular bull, the average period was 288i days, instead of 280; 

 none of these having gone less than 281 davs, and two-fifths of them having 

 exceeded 289 clays. 2 



763. Various states of the constitution, especially that which is designated 

 as "irritability," may induce the occurrence of the parturient effort at an 

 earlier period; and this constitutes Premature Delivery or Abortion, accord- 

 ing as the child is or is not viable ( 764). There are some women in whom 

 this regularly happens at a certain month, so that it seems to be an action 

 natural to them; but it should always be prevented, if possible, being inju- 

 rious alike to the mother and to the child ; and this prevention is to be at- 

 tempted by rest and tranquillity of mind and body, and by a careful avoid- 

 ance of all the exciting causes which may produce uterine contractions by 

 their operation on the Nervous system ( 760). Among the causes of Abor- 

 tion, however, the death of the fcetus, or an abnormal state of the placeutal 

 structure, is one of the most common; and thus we have another very dis- 

 tinct proof of the influence which the state of the contents of the uterus has 

 on the induction of the parturient effort. 



764. The question of the extreme limits of the period of Gestation, is one 

 of great importance both to the Practitioner and to the Medical Jurist. In 

 regard to the shortest period at which Gestation may terminate, consistently 

 with the viability of the Child, there is still a great degree of uncertainty. 

 Most practitioners are of opinion that it is next to impossible for a foetus -to 

 live and grow to maturity, which has not nearly completed its seventh 

 mouth ; but it is unquestionable that infants born at a much earlier period 

 have lived for some months, or even to adult age. It is rare in such cases, 

 however, that the date of conception can be fixed with sufficient precision to 

 enable a definite statement to be given. Of the importance of the question, 

 a case which some time since occurred in Scotland affords sufficient proof. 

 A vast amount of contradictory evidence was adduced on this trial ; but, on 



1 See Dr. J. C. Hall, in Medical Gazette. May 6th, 1842. 



2 The very ingenious doctrine has been propounded by Dr. Tyler Smith (Parturi- 

 tion, and the Principles and Practice of Obstetrics, London, 1849), that the exciting 

 cause of Parturition is to be found in the recurrence of the periodical excitement of 

 the ovary, acting by reflection on the uterus through the spinal system of nerves, the 

 ovarian nerves being the excitors, and the uterine the molors ; this excitement con- 

 tinuing during the entire period of gestation, and giving a special tendency to abor- 

 tion at each return; and acting with such potency at the eleventh recurrence as then 

 to induce the parturient eflbrt. He assigns no other cause, however, why this eleventh 

 recurrence should be so much more effectual than the rest, than that by this time 

 there is a much greater aptitude to contraction in the uterus itself, and an increased 

 readiness to be thrown otl' on the part of the placenta, conditions which seem to the 

 Author to be in themselves adequate to account fur the result. Dr. Tyler Smith's 

 hypothesis is distinctly negatived by the following facts: 1. The period of gestation, 

 although commonly a multiple of the menstrual interval, is by no means cvnstuntly 

 so; the former often remaining normal, when the latter is shorter or longer than 

 usual. 2. Parturient efforts ta'ke place in the uterus, notwithstanding the previous 

 removal of the lower part of the spinal cord. 3. The removal of the ovaries in the 

 later part of gestation does not interpose the least check to the parturient action, as 

 Prof. Simpson of Edinburgh has experimentally ascertained. The Author considers 

 himself fully justified, therefore, in asserting that this hypothesis does not possess the 

 slightest claim to be entertained as even & possible one; and would refer, for a more 

 detailed examination of it, to the Brit, and For. Med.-Chir. Review, vol. iv, p. 1. 



