contrary be shown. But where it is proved that the person has not been heard of for seven years, a presumption arises that he is dead. This presumption relates only to the fact of death; and the time of death whenever it is material, must be a subject of distinct proof, for the court will not presume the continuance of life up to the end, or to any precise point of the seven years.2

Where several persons have perished in the same calamity, the presumption is said to be in favour of the survival of the stronger party.3 But this doctrine has caused much controversy; and in a late case where it appeared that a husband, a wife, and their two children were washed off from the deck of a ship by the same wave and drowned; the Master of the Rolls held that in the absence of further evidence it must be presumed that all died at the same moment.1

By the law of marine insurance, if a vessel has sailed, and no tidings of her have been received within a reasonable time, she shall be presumed to have foundered at sea.5 And if a ship, shortly after sailing, shall, without visible or adequate cause, become leaky or otherwise incapable of performing the voyage insured, she shall be presumed to have been unseaworthy at the commencement of the risk.6 But this last rule does not appear to be quite established.7

Where goods have been lost or damaged while in the custody of a bailee or his servants, it is presumed that the loss or damage arises from his negligence. This presumption appears to arise as much in the case of a gratuitous bailee as in that of a bailee for valuable consideration; but the liability will be limited by the rules laid down in Coggs v. Bernard.8

1 Wilson v. Hodge, 2 East, 313.

2 Nepean v. Doe, 2 M. & W. 910; S. C. and 2 Sm. L. C. 308. 31 Phill. 479; Sillish v. Booth, 1 Y. & Col. 117.

4 Underwood v. Wing, 23 L. T. 339.

5 Tayl. 131.

6 Tayl. 132.

7 1 Phill. 471.

8 2 Lord Raym. 918; 1 Sm. L. C. 82, and notes.

Partners are presumed to have authority to bind their co-partners in all matters relating to the partnership, but not in matters unconnected with it.1

Finally, a large class of legal presumptions is contained in the technical and abstruse doctrine of estoppel.

"The law of estoppel is not so unjust or absurd as it has been too much the custom to represent. The principle is, that where a man has entered into a solemn engagement by deed under his hand and seal, he shall not be permitted to deny any matter which he has so asserted."2 The presumption is, that that is true which the deliberate act or statement of the party estopped has affirmed. But this presumption arises also from parol admission,3 and extends to all who are identified in interest with the estopped party.4

It is held that parties to deeds are concluded by recitals as to specific facts. In Bowman v. Taylor,5 Lord Denman said, "As to the doctrine laid down in Co. Litt. 352 b., that a recital doth not conclude because it is in direct affirmation, the authority of Lord Coke is a very great one; but still, if a party has, by his deed, recited a specific fact, though introduced by whereas,' it seems to me impossible to say that he shall not be bound by his own assertion so made under seal."

XXIX. A tenant cannot dispute his landlord's title.

"The security of landlords would be infinitely endangered if such a proceeding were allowed." But, although a tenant cannot be permitted to prove that his

1 Sandilands v. Marsh, 2 B. & Ald. 673; Bales v. Westwood, 2 Camp. 12.

2 Per Taunton, J., Bowman v. Taylor, 2 Ad. & El. 291.

3 Bringloe v. Goodsir, 5 Bing. N. C. 739.

4 2 Sm. L. C., notes to Duchess of Kingston's case.

5 Supra.

• Lord Ellenborough, Balls v. Westwood, 2 Camp. 12.

landlord never had any title, he may show that his title has expired.1

It is presumed that if a tenant show a receipt for rent, all previous rent has been paid by him to the landlord.2 A mortgagor in possession is presumed to have authority to distrain as the bailiff of the mortgagee.3

The above are examples of the principal presumptions of law which arise when a particular state of facts has been established. But an exhaustive treatment of the subject is beyond the limits of this work.

4

It has been remarked, that it is not very easy to distinguish those presumptions which are binding on a jury from those which they are at liberty to disregard and to negative by their verdict, even when not rebutted. It is also difficult to draw the precise line between conclusive and disputable presumptions; between those which operate in the nature of estoppel, and those which are merely primâ facie and rebuttable in character. The solution of the difficulty will be found in a clear comprehension of the law of estoppel. In Jayne v. Price, Heath, J. said, "Nothing can be clearer than this: a presumption may be rebutted by a contrary and stronger presumption ;" and it was decided in that case, that although proof of possession of land and permanency of rents is primâ facie evidence of a seisin in fee, yet proof of forty years' subsequent possession by a daughter, while a son and heir lived near and knew the fact, is much stronger evidence that the first possessor had only a particular estate.

CHAPTER V.

ON EVIDENCE IN MATTERS OF OPINION.

SINCE it is the province of the judge or of the jury, according to the principles of presumptive evidence, to draw all inferences from facts, it follows that,—

XXX. A witness must only state facts: and his mere personal opinion is not evi

dence.

The object of this rule is to keep the witness, as much as possible, from trespassing on the functions of either judge or jury; and it is relaxed as often as an opinion of a witness can be regarded in the nature of a presumptive fact. Thus in cases of insanity a medical witness cannot be asked whether he considers that the patient was insane, for that is the issue for the court and jury; but he may be asked whether certain symptoms are indications of insanity, and the answers are evidence for the guidance of the court and jury.1

In the leading case of Carter v. Boehm,2 it was a question whether a policy of insurance was vitiated by the concealment of facts which had not been communicated to the underwriters. A broker gave evidence of the materiality of the facts, and stated his opinion, that if they had been disclosed the policy would not have been underwritten; but the court held his statement to be inadmissible. Lord Mansfield said: "Great stress was laid upon the opinion of the broker; but we

1 R. v. M'Naghten, 10 Cl. & Fin. 200. 2 3 Burr. 1905; 1 Sm. L. C. 270.

all think the jury ought not to pay the least regard to it. It is mere opinion, which is not evidence; it is opinion after an event; it is opinion without the least foundation from any previous precedent or usage; it is an opinion which, if rightly formed, could be drawn only from the same premises from which the court and jury were to determine the cause, and, therefore, it is improper and irrelevant in the mouth of a witness."

This judgment of Lord Mansfield contains the principles on which mere opinion is not received as evidence. But it is right to state that his view of the law, as to this particular case, has been much controverted; and that it has been considered by other learned authorities,1 to come within the exceptions to the rule which is now to be stated; for it is held that

XXXI. The opinions of skilled or scientific witnesses are admissible evidence to elucidate matters which are of a strictly professional or scientific character.

In Campbell v. Rickards,2 Lord Denman, C. J., said,

"Witnesses conversant in a particular trade may be allowed to speak to a prevailing practice in that trade; scientific persons may give their opinions on matters of science; but witnesses are not receivable to state their views on matters of legal or moral obligation, nor on the manner in which others would probably be influenced if the parties had acted in one way rather than another. In the great case of Carter v. Boehm, a broker, who was called as a witness for the plaintiff, stated on cross-examination, that in his opinion certain letters ought to have been disclosed, and that if they

1 See note to Carter v. Boehm, 1 Sm. L. C. 25 B. & Ad. 846.