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the suppression of such riot, and as is not disproportioned to the danger which they, on reasonable grounds, believe to be apprehended from the continuance of the riot.1

If a gaoler or his officer is assaulted by a prisoner, in gaol or going to gaol, or by others in his behalf, provided the assault is made with a view of the prisoner's escaping, he will be justified in killing the assailant, whether a prisoner in civil or criminal suits, and this without first retreating.'

(3) A person who is in peaceable possession of real or personal property under a claim of right, and those acting under him, are protected from criminal responsibility for defending such possession, even against another person entitled by law to the possession of such property, if they use no more force than is necessary.3

155-56 V. c. 29, s. 42.

2 Fost. 321; 1 Hale, 481, 496; 55-56 V. c. 29, ss. 17, 18, 31, Dom, 355-56 V. c. 29, s. 49, Can.

B. C.-8

CHAPTER IV.

OF POISONS.

The author has been advised by a valued correspondent to omit this chapter in the present edition of this work, and no doubt some apology is required for not taking the advice. For a lawyer to attempt to instruct medical men in the subject of poisons, and indeed in any other branch of medical jurisprudence, is apparently a piece of presumption, and if these portions of the work were put forward as from the writer's own knowledge, the presumption would not only be apparent, but real. They are inserted, however, as concise and convenient extracts and compilations from the leading medical writers on the subjects, and in no way as his original productions. There is not a statement of any importance that cannot be verified by reference to standard authors, and in most cases the identical words of these authorities are made use of. The information given is consequently reliable, and it is believed will be found handy for reference by coroners and medical witnesses engaged upon inquests, and who have not always at hand more important works to refer to. It is impossible for medical men, not in the daily habit of teaching students, to bear in mind, all the effects and symptons of the various poisons, or to recall at any given moment, all the medico-legal knowledge they should have in their minds when suddenly called upon to perform a post-mortem, or to give evidence at an inquest, and while these portions of this work are not set forward as at all original or complete, it is hoped they contain enough to suggest to medical men much that may have been forgotten for the moment, or to at least put them on their guard, and so justify the retention of the chapter.

It may be remarked generally with regard to poisons that there are certain modifying circumstances connected with them, some of which relate to the poison itself, while others are connected with the system of the individual who takes the poison. Habit diminishes the power of poisons, particularly opium, alcohol and arsenic. Disease may modify or increase the action of poisons. In paralysis the action of strychnine is modified. tetanus and delirium tremens, opium is modified, and in apoplexy and inflammation of the brain, its action is increased. Sleep usually retards the

In

action of poisons, especially arsenic and irritants, but not of narcotics. Exercise accelerates the effects of all poisons except narcotics.1

Usually the action of poisons is more rapid when the dose is large. The form of the dose, whether solid or in solution, pure or admixed, will vary the symptoms, as will idiosyncrasy, state of health, etc.

A combination of poisons will in some cases increase, and in others decrease their effects. Others again will neutralize each other. The salts of calcium and the pottassium salts, by a careful equipoise in the dose-the one contracting the ventricle and the other relaxing it-can be made to neutralize each other. Veratrine and the potassium salts will act in a like manner. Arsenic is modified by alcohol, and probably other irritant poisons are also. Alcohol too modifies the effects of the bites of poisonous snakes. In a case where a large dose of corrosive sublimate and laudanum was taken a remarkable postponement of all the usual symptons is recorded. Prof. Reese also mentions the following poisons as found to be antagonizing in their influence, by his own experiments: Morphine and Atropine (in the human subject but not in cats and dogs); Atropine and Eserine; Atropine and Strychnine. He states also that there is good reason for admitting the antagonism between Aconite and Digitalis. He says Morphine and Prussic Acid, Strychnine and Prussic Acid, and Strychnine and Morphine, are not antagonistic.

1 Brown & Stewart, p. 320.

Of recent years a class of bodies called Ptomaines has attracted much attention and may here be briefly noted. The symptoms are of a narcotic irritant poison. Ptomaines have been found in decayed meat, cheese, sausages, certain shell-fish, canned meat and vegetables, milk, ice-cream, etc. They bear a strong resemblance to some of the vegetable alkaloids in their chemical and physiological reactions. Numerous ptomaines have been discovered in putrified human bodies, among which are a strychnine-like substance, a atrophine-like one, a veratrine-like, a conine-like, and a nicotine-like, ptomaine. These substances may interfere with the usual chemical tests and even cause a failure to discover strychnine and other alkaloids in a dead body, and raise a new difficulty for toxicologists, and suggest a new and plausible line of defence in trials for murder by poisoning. The importance of this subject is shown by an Italian criminal trial where the medical witness who performed the autopsy, gave it as his opinion that strychnia was probably present, while for the defence the great Selmi pointed out differences from strychnia, and said he considered the compound to be a ptomaine.1

Selmi obtained from a dead body, one month after death, a considerable amount of a crystallizable ptomaine, giving reactions like those of alkaloidal poisons, and having poisonous effects on frogs, and he has even supposed that death from various diseases may be due to the formation of these compounds.2

1 Brown & Stewart, p. 13.

2 Brown & Stewart, pp. 13, 14.

The subject of ptomaines cannot be treated at length in a work of this description, and is only mentioned to recall it to the mind of the medical witness and to put him on his guard when performing a post-mortem in a case of poisoning. If a trial follows he may hear a good deal about ptomaines, and he should take care before it is too late, to prepare himself for cross-examination on the subject.

The quantity of poison found in the stomach except of metallic poisons, is generally only a small fraction of the quantity taken, being merely the surplus beyond the fatal dose,' and it has in fact no direct connection with the fatal result, that being caused by the absorbed portion only."

The appearances common to dead bodies generally are often mistaken for the effects of poison.3

Unhealthy or improper food, or acute disease, may cause suspicious symptoms. This is a common solution of suspected poisoning.1

The results of experiments with poisons on animals, are not altogether conclusive as to man, but if a recent vomit proves poisonous to an animal, with the same symptoms as in the man, that is almost conclusive evidence.5

If possible, the approximate quantity of the poison should be ascertained and stated, particu

1 Browne & Stewart, p. 14.

2 Reese, p. 203.

3 Browne & Stewart, p. 15.
'Browne & Stewart, p. 15.
Browne & Stewart, p. 15.

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