McGill Faculty of Law: Extra-Contractual Obligations/Torts: Prof. Lara Khoury, 2002-03/Summary by Derek McKee
In terms of the means by which the harm is caused, Hughes v. Lord Advocate is the leading case. But this can be contrasted with Doughty v. Turner Manufacturing Co. Ltd. (1964), where a worker dealing with a cauldron of sodium cyanide was burned as a result of an unforeseeable kind of chemical explosion. Because the kind of explosion was unforeseeable, he lost.
In the case of Lamb v. Camden London Borough Council, Watkin LJ said that remoteness often depended on a judge’s “instinctive feeling.”
Many tort law textbooks try to portray these areas of the law in terms of clear rules when they are in fact very unclear.
thin skulls: disproportionate injury due to individual susceptibilities
Civil law gives priority to compensation.
Common law also gives priority to compensation: You must take the victim as you find him.
This contradicts the rule of foreseeability, both in its Wagon Mound 1 and Hughes versions. (Hughes, while allowing a broad range of foreseeability, still requires foreseeability—the thin skull rule doesn’t.)
Foreseeability and fault also matter.
Smith v. Leech Brain & Co. Ltd.,  2 Q.B. 405 (Q.B.D.). (CB2p153)
Smith operated galvanizing equipment at Leech Brain. The company only provided a kind of makeshift shelter to protect operators from splashes. Smith was accidentally burned on the lip by a piece of molten metal. The burn was not treated; it ulcerated and developed into cancer which killed Smith. However, long before this, Smith had worked in the gas industry, where he had been exposed to carcinogens. He probably had a pre-malignant condition of which the burn was the “promoting agency.”
Was the cancer (and the death) caused in part by the burn?
Lord Parker CJ noted that Wagon Mound 1 conflicted with the thin skull rule. But he held that the court in Wagon Mound 1 had not had the thin skull rule in mind, so he made an exception, and found the employers liable. The thin skull rule trumps foreseeability for causation.
However, when assessing damages, the court discounted damages for the cancer which would have occurred anyway, and awarded damages for the burn, and for having died earlier.
If a pre-existing susceptibility has already manifested itself before the accident, courts will try to hold the defendant liable only for aggravating the injury.
Common law calls these “crumbling skull” cases.
This is a direct application of the restitutio in integrum principle: we don’t want to enrich the victim.
Courts can assess the probability that something else would have caused the same injury.
G. Viney, Les conditions de la responsabilité (1998) (CB2p154)
French jurisprudence generally makes the same distinction: Pre-existing conditions do not exonerate the wrongdoer. However, they may reduce damages when the accident did not “realize or provoke” the affliction (i.e., “crumbling skulls”).
A pre-existing condition may also be used to reduce compensation if it was the result of a separate fault committed against the plaintiff.
Viney agrees with these principles; she thinks it would be dangerous to allow insurance companies to argue that their clients should not have to pay because the victim was abnormally fragile. This would essentially force the weak to suffer the consequences of their weakness.