 Solution

English law in 1867 fixed no maximum period of proved non-intercourse compatible with legitimacy; an exceptional interval had to be assessed on the evidence of possible gestation in the particular case. The relevant interval runs from the last possible intercourse between the spouses to the child's birth. Proof of subsequent non-intercourse establishes that interval; it does not itself establish how long pregnancy could have lasted.

The contemporary eighth edition of the Encyclopædia Britannica, published in 1853–1860, expressly distinguished the English position from numerical limits in continental codes. Its article on forensic medicine states: “The law of England at present has no definite limit”; it then says that a case beyond the usual term would go to a jury. This directly answers the legal question: there was no prescribed number of days that resolved every case. Medical evidence about the credibility of the claimed gestation informed the tribunal's decision about the child's status.^[ref]

To see what “consistent” means, distinguish the ordinary duration of pregnancy, the range alleged in exceptional medical reports, and a legal decision about a particular child. An accepted exceptional interval would show that the ordinary duration was not an inflexible rule; it would not establish a maximum for every subsequent case. For illustration, the later historical account in Legal medicine by Charles Meymott Tidy (volume 3) reports an English decision, dated there to 1834, allowing legitimacy after about 42 weeks, or 294 days, from last intercourse. This is a retrospective textbook report, not independent verification of the original judgment or proof of a longest accepted interval. The legal answer rests on the contemporary statement of the English rule, rather than on that numerical example.^[ref]

The medical evidence also requires care over the starting event. A period counted from the last menstruation is not the same measurement as a period counted from intercourse, and neither directly observes the instant of fertilization. Modern gestational age conventionally counts from the first day of the last menstrual period; early ultrasonography provides a more accurate check than menstrual recall alone. It would be misleading to combine historical figures with these different starting points into a single supposedly proved maximum.^[ref]

The absence of a predetermined English maximum did not make every length of separation legally acceptable or biologically possible. A claimed prolonged pregnancy still required credible evidence, and a nineteenth-century finding about legitimacy does not validate an extraordinary pregnancy length as a modern scientific observation. In historical legitimacy and prolonged gestation, the legal rule, the determination in an individual case, and the observed biological interval must be kept distinct. Establishing a unique longest reported case is a separate historical inquiry; it is not necessary to answer that English law prescribed no fixed maximum.